English Grammar Rules Reference — 60+ Core Rules with Examples and Common Mistakes

Present simple — habit, schedule, fact

Rule: Use the present simple for routines, general facts, scheduled events, and stative verbs. The verb takes -s/-es only with third-person singular subjects.

Why: Forgetting third-person -s is the #1 mistake. Facts always use simple present, not progressive — "water is boiling" describes a kettle right now, not a property of water.

Memory trick: He/she/it + verb-s. Everyone else: bare verb.

Present continuous — happening now / temporary / planned

Rule: Use am/is/are + V-ing for actions happening right now, temporary situations, or definite plans in the near future. Stative verbs (know, love, own, …) normally do NOT take -ing.

Why: Stative verbs describe a state, not a dynamic action — so they stay in simple form. "I know" not "I am knowing".

Memory trick: be + -ing = now / these days / fixed plan.

Present perfect — past action, present relevance

Rule: have/has + past participle. Use for past actions that still matter now: experience ("ever / never"), unfinished time ("this week / today"), or recent result ("just / already / yet"). Do NOT use with a finished-time phrase like "yesterday".

Why: Present perfect rejects specific past times. The moment you say "yesterday / in 2015 / two days ago", switch to simple past.

Memory trick: Still matters now → perfect. Done and dusted → simple past.

Present perfect continuous — duration up to now

Rule: have/has been + V-ing. Stresses the duration of an action that started in the past and is either still going on or has just stopped, often with visible result.

Why: Stative verbs (know, own, like) can't take -ing; switch to plain present perfect: "I have known him for ten years".

Memory trick: Started in the past, still warm right now.

Past simple — completed action at a specific past time

Rule: Verb + -ed (regular) or irregular form. Used with finished time expressions: yesterday, last week, in 1999, two hours ago. Question / negative uses did + bare verb.

Why: After "did", the main verb stays bare — "did visit" or just "visited", never "did visited". "Since" signals duration to now, so switch to present perfect.

Memory trick: Past time word + past form. After "did", main verb is bare.

Past continuous — ongoing past action / interrupted action

Rule: was/were + V-ing. Describes what was happening at a past moment, the longer of two simultaneous actions, or an action interrupted by another.

Why: Two-action rule: the long background action is past continuous, the short interrupting one is past simple. "while + -ing, when + -ed".

Past perfect — past before another past

Rule: had + past participle. Shows that one past action happened before another past action or time. Often signposted by before, after, by the time, when.

Why: In reported speech, present perfect "has" shifts back to past perfect "had". Two past actions with clear order → earlier one = had + p.p.

Memory trick: Past of the past = had + past participle.

Past perfect continuous — duration up to a past point

Rule: had been + V-ing. Stresses how long an action had been going on up to a specific past moment, often explaining the cause of a past result.

Why: If the main clause is past, push the duration clause back to had been -ing, not has been -ing.

Future with will — prediction / spontaneous decision / promise

Rule: will + bare verb. Use for predictions based on opinion ("I think it will rain"), spontaneous decisions made at the moment of speaking ("I'll get it!"), and promises / offers.

Why: "will" is for prediction based on opinion. For plans already made, use "be going to" or present continuous. For evidence right in front of you ("look at those clouds"), use "be going to".

Memory trick: Decide now → will. Decided before → be going to.

be going to — plan / evidence-based prediction

Rule: be going to + bare verb. Used for plans and intentions decided before the moment of speaking, and for predictions based on present evidence.

Why: Spontaneous offers use 'will' ("I'll help"). Pure opinion-based guesses also lean toward 'will' rather than 'going to'.

Future continuous — will be happening at a future time

Rule: will be + V-ing. Describes an action that will be in progress at a specific future moment, or a planned future action presented as a matter of course.

Why: For "what will be in progress at X o'clock", use will be -ing. It also softens future statements — "I'll be seeing her" sounds less abrupt than "I'll see her".

Future perfect — finished before a future time

Rule: will have + past participle. Says an action will be completed before a specific future time, often with "by + time".

Why: "by" + future time = future perfect (done by then). "in" + future time = simple future (done at that time).

used to + verb — past habit no longer true

Rule: "used to + bare verb" describes a past habit or state that has stopped. Question and negative use did: "Did you use to …?", "I didn't use to …" (drop the -d after did).

Why: Affirmative spelling is "used to". After "did" (questions/negatives) it becomes "use to" — the -d moves onto "did".

Memory trick: Plain: used to. After "did": use to.

would for past habits — repeated past actions

Rule: "would + bare verb" can describe repeated past actions, much like "used to". BUT "would" works only for actions, not for past states — for states (own, be, like) use "used to".

Why: "would" only covers repeated actions. For past states (own, be, like), it fails — switch to "used to have / used to be".

Memory trick: Repeated action → would. Past state → used to only.

be about to — on the verge of doing

Rule: "be about to + bare verb" means an action will happen in the very near future, often interrupted. "was about to" describes something nearly done in the past but stopped.

Why: "about to" takes a bare verb, never -ing. "about to leave", not "about to leaving".

Memory trick: be about to + base verb = right on the verge.

since-clause tense — perfect main, past sub-clause

Rule: With "since + a point in time as a clause", the main clause uses present perfect, and the since-clause uses simple past: "I have known her since we were children."

Why: Main clause = present perfect (lasting to now). The since-clause marks the past starting point → simple past. Don't make both perfect.

Future in the past — would / was going to

Rule: To express the future seen from a past viewpoint, use "would + bare verb" or "was/were going to + verb". Common in reported speech and narration: "He said he would come."

Why: When the main verb is past, the future shifts back: will → would, is going to → was going to. Sequence-of-tenses rule.

Memory trick: Future from the past: will becomes would.

Present simple for timetables — fixed future events

Rule: Use the present simple for scheduled future events fixed by a timetable: trains, flights, films, official programs. The schedule, not your plan, controls the timing.

Why: Timetabled events take present simple ("the train leaves at six"). Personal plans use present continuous or "be going to".

Stative verbs — no progressive form

Rule: Verbs of state (know, believe, understand, want, need, like, love, hate, own, belong, seem, contain) describe conditions, not actions, so they rarely take -ing.

Why: "I understand", not "I am understanding". A few verbs go dynamic with a shifted meaning: "I'm thinking" (considering), "I'm having lunch" (eating).

Memory trick: State verbs name a condition, so no -ing by default.

Present perfect vs past simple — the core contrast

Rule: Present perfect connects the past to now (no specific time, result still matters). Past simple is a finished event at a definite past time. The presence of a time expression usually decides which.

Why: Same event, two framings: "I have lost my keys" (still lost) vs "I lost them yesterday" (a dated event). A specific time flips you to past simple.

Memory trick: Dated time → past simple. Result-only → present perfect.

have been to vs have gone to

Rule: "have been to" = went and came back (experience). "have gone to" = went and is still there. They are not interchangeable.

Why: been to = visited and returned. gone to = away and still there. For life experience always "have you been to", never "gone".

Memory trick: been to = back. gone to = still away.

time markers — for / during / while with tenses

Rule: "for" + a length of time (for two hours). "during" + a noun naming a period (during the meeting). "while" + a clause with a verb (while I was sleeping).

Why: for + a duration, during + a noun-phrase period, while + a full clause. Three different grammatical objects.

Memory trick: for + length, during + noun, while + clause.

by vs until/till — deadline vs continuation

Rule: "by + time" = no later than that deadline (a single point of completion). "until / till + time" = an action continues right up to that time.

Why: "by" = a deadline for completing something. "until" = a continuous action lasting up to that time. "Finish by", "wait until".

Memory trick: by = deadline. until = lasts up to.

After "did", main verb stays base form

Rule: In questions and negatives with do/does/did, the main verb returns to its base form. The auxiliary already carries the tense and person, so the main verb must not.

Why: The auxiliary holds the tense, so the main verb is bare: "doesn't like", "didn't finish", "did go" — never doubled.

Memory trick: do/does/did present → main verb goes bare.

Relative clauses — that / which / who

Rule: Use "who" for people, "which" for things, and "that" for either in defining (restrictive) clauses. Never use "that" in a non-defining clause set off by commas — use "which" or "who".

Why: Commas kill "that". Also: "what" is never a relative pronoun in defining clauses — it's only for noun clauses ("what you said").

Memory trick: Commas → which/who. No commas → that is fine.

Relatives with preposition — formal vs informal

Rule: Formal: preposition + which/whom at the front of the clause. Informal: keep the preposition at the end and use that or zero relative. Never strand a preposition before "whom" or before "that".

Why: "in that" doesn't exist (no preposition before "that"). With "who", drop the preposition to the end. With "whom", you can put it up front.

Time clauses with future meaning — present, not will

Rule: In a time/condition clause (when, before, after, as soon as, until, if, unless, once …), use present tense to refer to the future, NOT will. The main clause keeps will.

Why: After when/if/before/after/until in future contexts: present in the clause, will in the main sentence — never two wills.

Memory trick: "Will" goes in the main clause; the time/if clause stays present.

Concession clauses — although / though / even though

Rule: Although / though / even though introduce a contrast. Do NOT pair them with "but" in the same sentence. "Though" can also work as an end-of-sentence adverb meaning "however".

Why: No "although … but …". Chinese 虽然…但是… maps to a single English connector, not both.

Memory trick: although XOR but. Never both.

Noun clauses — that as conjunction (sometimes optional)

Rule: "That" introduces a noun clause that functions as subject, object, or complement. As object after verbs like say, think, know, believe, the "that" can usually be dropped. As subject, "that" is required (or use the dummy "it … that …" structure).

Why: Object "that" = polite, drop-able. Subject "that" = structural, mandatory. When subject clause feels heavy, swap to "It is ... that ..." extraposition.

whether vs if — both mean "if/whether", but rules differ

Rule: After a preposition, before "to + V", at the start of a subject clause, or in formal writing → use whether. After verbs like ask, wonder, know → both whether and if are fine.

Why: "if to do" doesn't exist — always "whether to do". After prepositions, always "whether".

Memory trick: After preposition or before "to" → always whether.

Subjunctive — unreal present / future (Type 2)

Rule: If + past simple, … would + bare verb. Used for unreal or hypothetical present/future. Be is always "were" in this pattern (formal English).

Why: No "will / would" inside the if-clause — would lives in the main clause. Formal: "If I were you" (use "were" even with I/he/she).

Memory trick: Unreal present: if + past, would + base verb.

Subjunctive — unreal past (Type 3)

Rule: If + past perfect, … would have + past participle. Used for past situations that did NOT happen — pure regret or counterfactual.

Why: Never "If I would have ...". The if-clause takes past perfect; would have lives in the main clause only.

Memory trick: Unreal past: if + had + V3, would have + V3.

Subjunctive — suggest / insist / demand + (that) + base verb

Rule: After suggest, recommend, insist, demand, propose, request, require, the that-clause takes the bare infinitive (subjunctive), with no -s on third person and no tense agreement.

Why: After suggest/insist/demand/recommend, force "(should) + base verb" — drop the -s on third person, ignore tense agreement.

Memory trick: After suggest/insist/demand: bare verb, no -s.

Subjunctive — wish + past / past perfect / would

Rule: wish + past simple = regret about present; wish + past perfect = regret about past; wish + would = wish someone (else) behaved differently in future.

Why: No "wish I know". Use past for present regret, past perfect for past regret. "Wish + would" only works when wishing about someone else.

Memory trick: wish + past / past perfect / would — three flavors of regret.

Relative pronoun "whose" — possession

Rule: "whose" shows possession in a relative clause and works for both people and things: "the man whose car broke down", "a house whose roof is red".

Why: Don't split possession into "who … her". Use one word: "whose". It works for things too ("a house whose roof…").

Memory trick: Possessive in a clause → "whose", for people and things.

Relative adverbs — where / when / why

Rule: Use "where" after a place, "when" after a time, "why" after "reason". They replace "preposition + which": "the town where I grew up" = "the town in which I grew up".

Why: "the house which I was born" is wrong (no preposition). Use "where" or "in which". The relative adverb already contains the preposition.

Purpose clauses — so that / in order that

Rule: "so that" and "in order that" introduce a purpose clause, usually with a modal (can, could, will, would): "Speak up so that everyone can hear you."

Why: A purpose clause needs a modal (can/could/will/would). Note "so that" (purpose) differs from "so … that" (result).

Result clauses — so … that / such … that

Rule: "so + adjective/adverb + that" and "such + (a/an) + adjective + noun + that" both express result. The difference: "so" modifies an adjective/adverb, "such" modifies a noun phrase.

Why: "so" before a bare adjective/adverb ("so cold"); "such" before a noun phrase ("such a cold day"). Pick by what follows.

Memory trick: so + adjective/adverb, such + (a) noun.

Cause clauses — because / as / since

Rule: "because" gives the strongest, most direct reason and answers "why?". "as" and "since" give a reason already known or less emphatic. Don't pair "because" with "so" in the same sentence.

Why: No "because … so …" in one sentence — pick one. Also "because" + clause, "because of" + noun.

Memory trick: because XOR so. "because of" + noun.

Real conditionals — zero & first conditional

Rule: Zero conditional (general truth): If + present, present ("If you heat ice, it melts"). First conditional (likely future): If + present, will + verb ("If it rains, I'll stay in").

Why: No "will" in the if-clause. Zero conditional: present + present (truths). First conditional: present in the if-clause, "will" in the main clause.

Mixed conditionals — crossing time frames

Rule: Mix the unreal-past condition with an unreal-present result, or vice versa: "If I had studied medicine (past), I would be a doctor now (present)."

Why: Past condition + present result: "If I had done …, I would be …" (not "would have been"). Match each clause to its own time frame.

as if / as though — subjunctive for unreal comparison

Rule: After "as if / as though", use a past tense (or "were") to signal an unreal or unlikely comparison: "She talks as if she knew everything" (but she doesn't).

Why: For an unreal comparison, push the verb back: "as if he were". If the situation might be true, present tense is fine — but unreal needs the past/were.

Dummy "it" subject — It takes / It seems that …

Rule: Use a dummy "it" as a placeholder subject for clauses: "It takes time to learn", "It is important that you rest", "It seems that he left." The real clause comes later.

Why: When the real subject is a long to-clause or that-clause, put dummy "it" up front and shift the heavy part to the end. Dropping "it" leaves no subject.

Concession — no matter how / however / whatever

Rule: "No matter how/what/where" and "however/whatever/wherever" introduce a concession meaning "regardless". "However + adjective/adverb" comes first, then subject + verb.

Why: "However" attaches directly to the adjective/adverb: "however rich he is", not "however he is rich". Keep that word order.

Memory trick: however + adjective + subject + verb. Keep the order.

Negative fronting — never, seldom, rarely, hardly

Rule: When you put a negative or restrictive adverb at the start (never, seldom, rarely, hardly, scarcely, not only, no sooner, little, in no way), invert subject and auxiliary like a question.

Why: Front a negative → invert. "Never I have seen" is always wrong; it must be "Never have I seen".

Memory trick: Negative at the front → auxiliary jumps before the subject.

Inversion after "only + adverbial"

Rule: When "only + a time/place/condition phrase" begins a sentence, the main clause inverts. The inversion happens in the main clause, NOT inside the only-phrase.

Why: After "only + adverbial", invert the verb. "Only then I realized" → "Only then did I realize".

So / Neither / Nor — "me too / me neither" inversions

Rule: To agree with a positive statement: So + auxiliary + subject. To agree with a negative: Neither / Nor + auxiliary + subject. The auxiliary matches the original sentence's tense.

Why: "So do I" = me too. "So I do" = a different idiom meaning "indeed I do". Neither/Nor also force inversion: "Neither can I", not "Neither I can".

Memory trick: So/Neither + aux + subject. Three slots.

Conditional inversion — drop "if"

Rule: You can drop "if" and invert the auxiliary to the front. Common with had, were, should: Had I known → If I had known. More formal in tone.

Why: Either "If I had known" OR "Had I known" — never both. The verb after "had" must be a past participle.

Locative inversion — Here / There / In the corner …

Rule: When a place adverbial starts the sentence and the verb is intransitive (come, go, sit, lie, stand, hang, be), invert subject and verb. EXCEPTION: if the subject is a pronoun, NO inversion.

Why: Noun subject → invert ("Here comes the bus"). Pronoun subject → no inversion ("Here it comes!").

Emphatic do — adds stress in affirmative sentences

Rule: In an affirmative present or past sentence, add do/does/did before the bare verb to stress that the action really happens. Common in contradictions or strong affirmations.

Why: Once you add emphatic do/does/did, the main verb must go back to bare form — no -s, no -ed.

Memory trick: Emphatic do → main verb goes bare.

It-cleft — It is X that …

Rule: Use "It is/was + emphasized element + that/who + rest of sentence" to focus on any noun phrase, adverbial, or prepositional phrase. The verb in the cleft agrees with "it" (singular).

Why: "It" stays singular: "It was them", not "It were them". And use "that" (not where/when) in the cleft.

Ellipsis — drop repeated words after to / and / but

Rule: After "to" (infinitive of purpose) you can drop the repeated verb: "I want to go but I don't have time to." After and / but the subject + auxiliary can be dropped if identical: "She arrived and (she) sat down."

Why: "I forgot" alone = forgot the whole thing. "I forgot to" = forgot to do that specific action. Keep the lonely "to" — it carries the meaning.

Fronting "So / Such" + adjective → inversion

Rule: When "So + adjective" or "Such + noun" is fronted for emphasis, the clause inverts: "So beautiful was the sunset that we stopped." "Such was his anger that he left."

Why: Front "So + adjective" and the verb jumps before the subject: "So loud was the music". A formal emphasis pattern.

Concessive inversion — Adjective + as/though + subject

Rule: Put an adjective/adverb first, then "as" or "though", for a concession: "Tired as he was, he kept working" = "Although he was tired…".

Why: "Adjective + as + subject + verb" means "although". Don't add "although" too — this fronted form already carries the concession.

Reporting inversion — "…," said the man

Rule: After a direct quotation, when the subject is a noun, you may invert: '"Hello," said Tom.' With a pronoun subject, do NOT invert: '"Hello," he said.'

Why: Noun subject can invert ("said Mary"); pronoun subject cannot ("he said"). "said she / said he" sounds archaic — avoid.

Inversion after "Not until …"

Rule: When "Not until + time/clause" is fronted, the MAIN clause inverts (not the until-clause): "Not until midnight did he arrive."

Why: Front "Not until …" and the main clause inverts ("did he arrive"). The until-clause itself keeps normal word order.

No sooner … than / Hardly … when

Rule: For "as soon as one thing happened, another did", front "No sooner" (→ than) or "Hardly/Scarcely" (→ when), and invert: "No sooner had I left than it rained."

Why: Pairings matter: "No sooner … than", "Hardly/Scarcely … when". The earlier clause is past perfect (had done), the later one past simple.

Memory trick: No sooner … than. Hardly … when.

Inversion with "may" — wishes and blessings

Rule: To express a wish or blessing in a formal/literary way, put "may" before the subject: "May you live long!", "May all your dreams come true."

Why: "May + subject + base verb" = a wish (inverted). Different from "you may …" (permission), which keeps normal order.

Wh-cleft — What I need is …

Rule: A wh-cleft puts the focus at the end: "What I need is a holiday", "What surprised me was his calm." The clause "What …" acts as the subject.

Why: In "What I need is …", the "What" clause is a singular subject, so the verb is "is/was". It pushes the key info to the end for focus.

Object fronting for emphasis

Rule: You can move an object to the front for contrast or emphasis, keeping normal subject-verb order: "That book I have read; this one I haven't."

Why: Fronting an object for emphasis usually keeps subject-verb order ("That I can believe"), unlike negative-adverb fronting which forces inversion.

a vs an — based on sound, not spelling

Rule: Use "an" before a vowel SOUND, "a" before a consonant sound. Spelling can mislead: an hour, an MBA, a university, a one-way street.

Why: Don't look at the first letter — listen to the first sound. "hour" starts with a vowel sound, "university" starts with a consonant sound (y-ou).

Memory trick: Sound, not spelling. Vowel sound → an. Consonant sound → a.

When to use "the" — specific / unique / second mention

Rule: Use "the" when the listener already knows which one: previously mentioned, unique (the sun, the President), specified by clause/phrase (the book on the table), superlatives (the best), or ordinal (the first).

Why: Chinese has no articles, so Chinese learners systematically drop "the". Anything unique or already-known to the listener needs it.

Zero article — generic plural / uncountable / meals / sports

Rule: Use NO article for generic plural nouns ("Dogs bark"), uncountable nouns in a general sense ("Water is essential"), meals ("have lunch"), sports ("play tennis"), languages ("speak French"), and most countries.

Why: Generic plural / uncountable = no article. But instruments are the opposite: "play the piano". Sports never take "the".

Memory trick: Generic plural / uncountable / meals / sports / languages → zero article.

"the" with countries, geography, and proper nouns

Rule: Most countries take NO article (China, France, Japan), BUT plural names, "kingdom/republic/states", and rivers/seas/oceans/mountain ranges DO take "the": the United States, the Netherlands, the Nile, the Pacific, the Alps.

Why: Plural country names ("the Netherlands"), names with "united/kingdom/republic", and ranges/rivers/oceans take "the". Single mountains and lakes don't: "Mount Fuji", "Lake Tahoe".

Institution nouns — "to school" vs "to the school"

Rule: For institutions used for their main purpose, drop the article: go to school / to bed / to church / to hospital / to prison (BrE). When you visit the building for any other reason, use "the".

Why: Drop "the" when using the institution for its purpose (sleeping in bed, studying at school). Add "the" when you're just visiting the building.

Memory trick: Going to do its job → no "the". Just visiting → add "the".

Articles with titles — Doctor Smith vs the doctor

Rule: Title + proper name = no article: Doctor Smith, President Lincoln, Queen Elizabeth. Title alone, used as a common noun, takes the article: the doctor, the president, the queen.

Why: Title + name = no article. Title alone usually takes "the" because you mean a specific person.

a/an with jobs and nationalities

Rule: Use "a/an" before a singular job, role, or religion: "She is a doctor", "He is an engineer." This differs from Chinese, which omits the article.

Why: "She is a teacher" — the article is required for singular jobs. Chinese drops it, so learners forget. Plural jobs take none: "They are teachers".

Memory trick: Singular job or role → always a/an.

"the" with superlatives, ordinals, and "only"

Rule: Superlatives ("the best"), ordinal numbers ("the first"), and "only" ("the only one") all take "the" because they single out a unique item.

Why: Superlatives, ordinals, and "only" point to a unique item, so they need "the": "the best", "the first", "the only".

Memory trick: Superlative / ordinal / only → take "the".

No "a/an" before uncountable nouns

Rule: Uncountable nouns (information, advice, furniture, news, equipment, luggage) take no "a/an" and no plural -s. To count them, use "a piece of / a bit of".

Why: advice / information / furniture / news / luggage are uncountable — no "an advice", no "furnitures". Count them with "a piece of".

Memory trick: Uncountables: no a/an, no plural -s.

"the" with musical instruments

Rule: When talking about playing a musical instrument in general, use "the": "play the piano", "play the guitar." (But sports take no article: "play football".)

Why: Instruments take "the" ("play the piano"); sports take none ("play football"). They're mirror opposites — easy to mix up.

Memory trick: Instruments → the. Sports → no article.

"the … the …" — the more, the better

Rule: The pattern "the + comparative …, the + comparative …" expresses that two things change together: "The more you practice, the better you get."

Why: For "the more …, the more …", keep both "the"s and front each comparative. Don't drop the article or scatter the order.

Memory trick: the + comparative, the + comparative = "the more … the more".

"the" with decades, adjectives-as-nouns, and groups

Rule: Use "the" with decades ("the 1990s"), with adjectives used as plural nouns for a group ("the rich", "the elderly"), and with nationality groups ("the Chinese").

Why: "the rich" = rich people as a group (plural verb). Decades take "the" ("the 1980s"). No Chinese equivalent, so memorize.

in / on / at — for time

Rule: at + clock time / festival: at 7 p.m., at Christmas. on + day / date: on Monday, on July 4. in + month / year / season / longer period: in March, in 2026, in summer, in the morning.

Why: Smaller time unit → smaller-mouthed preposition: at (point) → on (day) → in (longer span).

Memory trick: at point / on day / in span. Three steps up.

in / on / at — for place

Rule: at + a specific point or address (at the door, at 23 Elm Street). on + a surface or line (on the table, on the wall, on the bus). in + an enclosed space or large area (in the room, in the car, in Beijing).

Why: "in" for cars / taxis (enclosed, small), "on" for buses / trains / planes (you can walk around). Memorize this pair.

by / with / of — agent, instrument, possession

Rule: by = doer of action (passive) or means of travel (by car, by bus). with = instrument or accompaniment (with a knife, with my brother). of = possession or composition (the legs of the table).

Why: Passive agent → "by". Tool → "with". "Cut with a knife", not "cut by a knife".

for vs since — duration vs starting point

Rule: for + a length of time (for three years, for two hours). since + a starting point in time (since 2020, since Monday). Both typically take present perfect or present perfect continuous.

Why: "Since" needs a point, "for" needs a duration. "Since ten years" doesn't exist — say "for ten years".

Memory trick: for + span. since + point. One stretches, one starts.

between vs among

Rule: between = two distinct items (you can also use it for 3+ when each is named individually). among = three or more, viewed as a group.

Why: Two named parties → between. A blurry group → among. "Among" with just two parties is wrong.

in vs into / on vs onto — static vs movement

Rule: in / on describe a static location. into / onto describe movement from outside into or onto something.

Why: Movement INTO a container → into. Movement onto a surface → onto. Already there → in / on.

"different from / than / to" — which to use

Rule: "Different from" is universally accepted. "Different than" is common in American English, especially before a clause. "Different to" is common in British English. In formal writing, prefer "different from".

Why: Never "different of / different with". Stick to "different from" if unsure.

arrive at / in / [no preposition for home]

Rule: arrive at + a specific point (at the station, at the airport). arrive in + a city, country, or large area (in Beijing, in Japan). arrive home / here / there: NO preposition.

Why: Never "arrive to". And "home / here / there" are adverbs after arrive — no preposition at all.

to vs for — direction vs purpose/benefit

Rule: "to" marks a destination or recipient (give it to me, go to school). "for" marks purpose, benefit, or duration (a gift for you, study for the exam).

Why: Recipient/direction → "to" (give to me). Benefit/purpose → "for" (a gift for you). Note "buy for", "give to".

Verb + preposition pairs — look at / listen to / wait for

Rule: Many verbs require a fixed preposition: look at, listen to, wait for, depend on, belong to, agree with, apologize for. These cannot be guessed from the meaning.

Why: "listen to me" (not "listen me"), "wait for the bus", "depend on" (not "depend of"). These are fixed — memorize, don't guess.

Memory trick: listen to / wait for / depend on — fixed pairs.

on / about / of — topic prepositions

Rule: "about" = a general, everyday topic (a film about war). "on" = a formal or academic subject (a lecture on economics). "of" pairs with specific nouns (the idea of, news of).

Why: Everyday topic → about. Formal/academic subject → on (a book on physics). Fixed phrases → of (the idea of).

across / through / over — crossing prepositions

Rule: "across" = over a flat surface or line (across the street). "through" = inside something with volume (through the tunnel, through the forest). "over" = above or covering (jump over the wall).

Why: Flat surface → across (the street). Enclosed volume → through (the tunnel). Above/covering → over (the wall).

beside vs besides

Rule: "beside" = next to, at the side of (sit beside me). "besides" = in addition to / apart from (besides English, she speaks French). One letter, very different meanings.

Why: beside = next to (position). besides = in addition / apart from. The extra "s" flips the meaning.

Memory trick: beside = next to. besides = in addition. Extra s, extra meaning.

in time vs on time

Rule: "on time" = punctual, exactly at the scheduled moment. "in time" = early enough, with some margin before a deadline or event.

Why: on time = exactly punctual. in time = early enough, with a margin. Train runs on time; you arrive in time.

Memory trick: on time = punctual. in time = with a margin to spare.

at the end vs in the end

Rule: "at the end (of)" = at the final point of something physical or in time (at the end of the street / the film). "in the end" = finally, after all (an outcome).

Why: "at the end of" + a concrete end-point. "in the end" stands alone meaning "finally / as an outcome".

made of / made from / made in / made by

Rule: "made of" = material still visible (a table made of wood). "made from" = material changed in process (wine made from grapes). "made in" = place. "made by" = maker.

Why: made of = material still recognizable (gold ring). made from = transformed (paper from wood). made in = place; made by = maker.

Memory trick: of = visible, from = transformed, in = place, by = maker.

Passive structure — be + past participle

Rule: Active object becomes passive subject. The verb changes to "be + past participle" in the same tense. The active subject becomes "by + agent" (often omitted).

Why: After "be", use past participle (written, broken), not past simple (wrote, broke). Agent is introduced by "by", not "from".

Memory trick: Passive = be + V3. Agent rides on "by".

Passive in different tenses

Rule: Keep the original tense by changing only "be": is/are done (present), was/were done (past), has been done (present perfect), will be done (future), is being done (present continuous).

Why: Progressive passive: be + being + V3 (two be-forms!). Perfect passive: have/had + been + V3. Don't lose either auxiliary.

Verbs that CAN'T go passive — intransitive / state

Rule: Intransitive verbs (happen, occur, arrive, die, exist, belong, last, seem, look) have no object, so they cannot form a passive. State verbs like resemble, have (= possess), fit, suit also resist passivization.

Why: "was happened / was arrived" are always wrong. These verbs never go passive — they're intransitive (no object to promote).

Memory trick: happen / occur / arrive / die — always active, no "be".

Passive agent — by (doer) vs with (tool) vs in (material)

Rule: by + the doer of the action. with + the instrument or material used. in / of + the substance composing the thing.

Why: Three-way split: made by Grandma (agent), cut with a knife (tool), made of marble (material). Mixing them changes meaning.

Double-object verbs — give / send / show have two passives

Rule: Verbs like give, send, show, tell, offer, teach have two objects (indirect + direct). Either object can become the passive subject, giving two valid passive sentences.

Why: If the indirect object becomes subject, the direct object stays as-is. If the direct object becomes subject, the indirect object needs "to" / "for".

Reporting passives — It is said that … / He is said to …

Rule: Verbs like say, believe, think, report, know have two passive forms: (1) It + be + said/thought + that-clause, or (2) Subject + be + said/thought + to-infinitive. Common in news writing.

Why: Pick ONE: "It is said that he is …" OR "He is said to be …". "to be" = same time; "to have been" = earlier than the reporting.

Passive with modals — can/must/should + be + V3

Rule: To make a modal verb passive, use "modal + be + past participle": "It must be done", "This can be improved", "The form should be signed."

Why: Don't drop "be" after the modal: "must be done", "can be solved". The "be" carries the passive — losing it breaks the structure.

Memory trick: Modal passive = modal + be + V3. Never lose "be".

Get-passive — informal, often unexpected events

Rule: In informal English, "get + past participle" replaces "be" for events, often sudden or negative: "He got fired", "The window got broken", "They got married."

Why: "get + V3" is the informal passive, stressing that something happened to someone (often unexpectedly). Formal writing still prefers "be".

Passive of phrasal verbs — keep the particle

Rule: When a phrasal verb goes passive, the particle stays attached: "look after → be looked after", "put off → be put off", "deal with → be dealt with."

Why: Keep the particle in the passive: "be looked after", "be put off", "be dealt with". Dropping it leaves the verb incomplete.

Memory trick: Phrasal verb passive → the particle stays put.

Causative passive — have/get something done

Rule: "have/get + object + past participle" means you arrange for someone else to do something: "I had my hair cut", "She got her car repaired."

Why: "have/get sth done" = someone else did it for you. "I had my hair cut" (a barber did it), not "I had cut my hair" (you did, past perfect).

Memory trick: have/get + thing + V3 = you arrange it, someone else does it.

When to choose passive over active

Rule: Prefer the passive when the doer is unknown, obvious, or unimportant, or when you want to focus on the action/result: "The bridge was built in 1890", "Mistakes were made."

Why: Use the passive when the agent is unknown or irrelevant, or to foreground the action. Common in science, news, and instructions.

need / want / require + -ing (passive meaning)

Rule: After "need", "want", or "require", an -ing form carries a passive meaning: "The car needs washing" = "needs to be washed." Both forms are correct.

Why: "needs washing" = needs to be washed (passive). "needs to wash" wrongly means the car does the washing. The -ing is passive here.

Memory trick: need + -ing = need to be done. Built-in passive.

Gerund vs infinitive — verbs that change meaning

Rule: Some verbs (remember, forget, stop, try, regret, mean) change meaning depending on whether they take a gerund or an infinitive. Memorize the pairs.

Why: remember/forget + -ing = recall a past action. + to V = remember/forget the duty ahead. stop + -ing = quit. stop + to V = pause in order to.

Memory trick: -ing looks back, to-V looks ahead.

After a preposition, always use gerund

Rule: Any verb following a preposition must be in -ing form, never to-infinitive. This includes "to" when "to" is a preposition (look forward to, be used to, get used to, object to, in addition to).

Why: "to" after "look forward / be used / object / in addition" is a preposition, not the infinitive marker. So it takes -ing, not bare verb.

Memory trick: Preposition → -ing. Watch whether "to" is preposition or infinitive marker.

Causatives — make / let / have + object + bare verb

Rule: "make sb do", "let sb do", "have sb do" — bare infinitive (no "to"). But in the passive, "make" takes "to": sb is made to do sth.

Why: Active "make sb do" (no to). Passive "sb is made TO do" (with to). The "to" appears only in the passive — counter-intuitive but tested.

Memory trick: Active make = no to. Passive made = "to" returns.

Perception verbs — see / hear / watch + bare verb / -ing

Rule: "see/hear/watch sb do sth" = saw the whole thing. "see/hear/watch sb doing sth" = saw it in progress. Active uses bare verb / -ing; passive switches to "to + verb" / "doing".

Why: Active perception verb → bare verb. Passive → "to + verb". Same pattern as make/let/have.

Present participle — V-ing as adjective / adverbial

Rule: V-ing can modify a noun ("the running water") or act as an adverbial showing time, cause, manner, or accompanying action ("Walking down the street, I saw…").

Why: A dangling participle = wrong subject. "Walking down the street, the building collapsed" sounds like the building walked. Make the doer match.

Past participle — V-ed as adjective / passive meaning

Rule: V-ed (or irregular V3) used as an adjective conveys passive or completed sense: "broken window" (already broken), "written language", "the man dressed in black".

Why: Past participle = passive/done. Present participle = active/ongoing. "boring" describes the thing, "bored" describes how you feel.

Memory trick: -ed = done to it. -ing = doing it itself.

Dangling participle — match the subject

Rule: When a participle phrase opens a sentence, its logical subject must be the same as the subject of the main clause. Otherwise the sentence "dangles" and sounds wrong or comical.

Why: The unstated subject of the participle must equal the main clause subject. Mismatch = the bed gets tired, the deer walks itself.

Infinitive of purpose — to / in order to / so as to

Rule: Use "to + V" to express purpose. For emphasis or formality, use "in order to" or "so as to". "for + V-ing" is wrong for purpose: "I came to learn", NOT "I came for learning".

Why: Purpose = "to + V" (or in order to / so as to). "for + V-ing" expresses function ("a knife for cutting"), not purpose.

Memory trick: Purpose → to + V. Function → for + V-ing.

Gerund as subject — Smoking is bad

Rule: A gerund (V-ing) can be the subject of a sentence and takes a singular verb: "Swimming is fun", "Reading helps." Don't use a bare infinitive as a casual subject.

Why: Gerund subjects take a singular verb ("Swimming is fun"). "To swim is fun" is also correct but more formal.

Memory trick: Gerund subject → singular verb.

Verbs followed only by gerund — enjoy, finish, avoid

Rule: Some verbs take only a gerund, never an infinitive: enjoy, finish, avoid, mind, suggest, practise, consider, keep, give up, can't help.

Why: enjoy / finish / avoid / mind / suggest take only -ing, never "to". "enjoy to read" is wrong → "enjoy reading".

Memory trick: enjoy / finish / avoid / mind → -ing only.

Verbs followed only by infinitive — want, decide, hope

Rule: Some verbs take only a to-infinitive, never a gerund: want, decide, hope, plan, agree, refuse, promise, manage, offer, learn, expect.

Why: want / decide / hope / plan / agree take only "to + verb", never -ing. Opposite of the enjoy/finish group.

Memory trick: want / decide / hope / plan → to + verb only.

too … to / enough … to — infinitive of degree

Rule: "too + adjective + to do" = so much that you can't (too tired to walk). "adjective + enough + to do" = sufficiently (old enough to drive). Word order: enough comes AFTER the adjective.

Why: "too … to" already means "so … that not" — don't add "not". And "enough" follows the adjective: "old enough", not "enough old".

Memory trick: "too … to" = already negative. "enough" follows the adjective.

It + adjective + to do / of sb to do

Rule: Use "It is + adjective + (for sb) to do" for difficulty/possibility, but "It is + adjective + of sb to do" when judging someone's character: "It was kind of you to help."

Why: Difficulty/possibility → "for sb" (hard for me). Judging character → "of sb" (kind of you, silly of him).

Memory trick: Difficulty → for sb. Character → of sb.

Perfect participle — Having done …

Rule: "Having + past participle" shows an action completed before the main clause: "Having finished dinner, we went out." It stresses the earlier action.

Why: "Having + V3" = after doing. The subject must match the main clause. Passive form: "Having been + V3".

Bare infinitive after modals and "had better / would rather"

Rule: After modal verbs (can, must, should, will) and after "had better", "would rather", "why not", use the bare infinitive — no "to".

Why: No "to" after "had better" or "would rather": "had better leave", not "had better to leave". Same as after modals.

Memory trick: had better / would rather + bare verb. No "to".

further vs farther

Rule: "farther" = physical distance only. "further" = both physical distance AND figurative / additional sense ("further details", "further research"). In doubt, use "further".

Why: Physical distance: both work. Abstract / additional: only "further". When unsure, "further" is the safe choice.

Memory trick: Distance = either. Abstract = further only.

fewer vs less

Rule: "fewer" + countable plural nouns: fewer cars, fewer mistakes. "less" + uncountable nouns: less water, less time, less money. Time/money/distance often use "less" even when technically countable.

Why: Supermarket signs say "10 items or less" — that's technically wrong. Formal writing uses "fewer" with countables.

Memory trick: Countable → fewer. Uncountable → less.

who vs whom

Rule: "who" is the subject (he/she/they replace it). "whom" is the object (him/her/them replace it). After a preposition: always "whom" in formal English ("to whom", "with whom"). In casual speech, "who" often replaces "whom".

Why: Trick: rewrite as a statement. If "he" fits → who. If "him" fits → whom. Both end in m: him/whom.

Memory trick: Answer is "he" → who. Answer is "him" → whom. The m matches.

affect vs effect

Rule: "affect" is usually a verb (= to influence). "effect" is usually a noun (= the result). Exceptions: "to effect a change" (verb, formal = bring about) and "affect" as noun in psychology (= emotion).

Why: Trick: "affect" = action (verb), "effect" = end-result (noun). Most of the time, that's all you need.

Memory trick: A = action verb. E = end-result noun.

its vs it's

Rule: "its" = possessive (the dog wagged its tail). "it's" = contraction of "it is" or "it has". If you can expand it to "it is / it has" and it makes sense, use "it's". Otherwise, "its".

Why: Possessives never use apostrophes (his / hers / theirs / its). The apostrophe is reserved for contractions.

Memory trick: Expandable to "it is" → it's. Otherwise → its.

their / there / they're

Rule: "their" = belonging to them. "there" = in/at that place, or dummy subject ("there is …"). "they're" = contraction of "they are".

Why: Three identical sounds, three different jobs. Possessive (their), place (there), contraction (they're).

then vs than

Rule: "then" = at that time or next ("First A, then B"). "than" = used in comparisons ("bigger than that"). They look similar but have totally different jobs.

Why: Comparison → than (a for "as compared"). Time/sequence → then (e for "ensuing").

lay vs lie

Rule: "lay" (laid, laid) = to put something down — needs an object: "I lay the book on the table." "lie" (lay, lain) = to recline — no object: "I lie on the bed." NOTE: the past of "lie" is "lay" — that's the trap.

Why: Today I lie / yesterday I lay / I have lain (no object). vs. Today I lay / yesterday I laid / I have laid (with object). The overlap of "lay" is what trips everyone.

much vs many vs a lot of

Rule: "much" + uncountable (much water). "many" + countable plural (many books). "a lot of / lots of" + both, more common in spoken English. In affirmative sentences, "much" and "many" sound formal; "a lot of" is preferred in everyday speech.

Why: Uncountable → much. Countable plural → many. "Waters" works only when you mean cups/bottles of water, not water in general.

Memory trick: Uncountable → much. Countable → many. Speech → a lot of.

borrow vs lend

Rule: "borrow" = to take and use temporarily (I take from you). "lend" = to give for temporary use (I give to you). The direction is opposite.

Why: I borrow from you (I take). You lend to me (you give). Chinese 借 covers both directions; English forces you to pick.

Memory trick: borrow = take. lend = give. Opposite arrows.

advice vs advise

Rule: "advice" (noun, /s/ sound) = a recommendation. "advise" (verb, /z/ sound) = to recommend. Same split as practice/practise, device/devise.

Why: Noun "advice" (uncountable), verb "advise". "give advice", "advise sb to do". The c sounds /s/, the s sounds /z/.

Memory trick: advice = noun (/s/). advise = verb (/z/).

accept vs except

Rule: "accept" (verb) = to receive or agree to. "except" (preposition/conjunction) = not including, apart from. They sound similar but do opposite jobs.

Why: "accept" = to take/agree (verb). "except" = apart from (preposition). Similar sound, opposite roles.

Memory trick: accept = take in. except = leave out.

principal vs principle

Rule: "principal" = main/chief (adjective) or head of a school (noun). "principle" = a rule or fundamental truth (noun only). Tip: the principAL is your pAL; a principLE is a ruLE.

Why: principAL = main, or your pAL the head teacher. principLE = a ruLE. Match the endings to remember.

Memory trick: principAL = pAL (main / head). principLE = ruLE.

stationary vs stationery

Rule: "stationary" (with an a) = not moving, still. "stationery" (with an e) = writing materials like pens and paper. Tip: stationEry = Envelopes/pEns.

Why: stationAry = stAnding still. stationEry = pEns and Envelopes. The vowel before -ry tells them apart.

Memory trick: stationAry = stAnd still. stationEry = pEn & Envelope.

loose vs lose

Rule: "loose" (adjective, rhymes with "goose") = not tight. "lose" (verb, rhymes with "choose") = to misplace or not win. One o vs two.

Why: loose = not tight (double o, /s/). lose = misplace/not win (single o, /z/). Native speakers slip here too.

Memory trick: loose = extra o, not tight. lose = lost an o, misplaced.

bring vs take

Rule: "bring" = movement toward the speaker/listener (bring it here). "take" = movement away (take it there). The direction relative to the speaker decides.

Why: bring = toward here (come). take = toward there (go). Both pivot on where the speaker stands.

Memory trick: bring = toward me. take = away from me.

rise vs raise

Rule: "rise" (rose, risen) = to go up by itself — no object. "raise" (raised, raised) = to lift something — needs an object. The sun rises; you raise your hand.

Why: rise = goes up on its own (no object). raise = lift something (needs an object). "the sun rises", "raise your hand".

Memory trick: rise = goes up itself. raise = lifts something.

complement vs compliment

Rule: "complement" (with an e) = something that completes or goes well with. "compliment" (with an i) = a word of praise. Tip: complEte → complEment; I like to give a complIment.

Why: complEment = completes (think complEte). complIment = praise (I give a complIment). Wine complements; people compliment.

Memory trick: complEment = complEtes. complIment = praise (I give one).

everyday vs every day

Rule: "everyday" (one word, adjective) = ordinary, common (everyday clothes). "every day" (two words) = each day (adverbial of frequency).

Why: "every day" (two words) = each day (when). "everyday" (one word) = ordinary (adjective). "I run every day", "everyday clothes".

Memory trick: every day = each day (2 words). everyday = ordinary (1 word).

comparative vs superlative — than vs of/in

Rule: Comparative (–er / more) compares two and pairs with "than": "taller than me". Superlative (–est / most) picks one from three or more and pairs with "the … in/of": "the tallest in the class".

Why: Two items → comparative + than. Three or more → superlative + "the … in/of". "smart" is short, so "smarter / the smartest", not "more smart".

Memory trick: Two → comparative + than. 3+ → superlative + the … in/of.