Auxiliary verb

• ✅ Do you know? — ❌ Know you? (English requires do-support for questions)
• ✅ She has finished. — ❌ She finished has. (auxiliary before main verb)
• ✅ They are leaving. — ❌ They leaving. (progressive needs be)
• ✅ He doesn't smoke. — ❌ He smokes not. (negation needs do)

Auxiliary verbs (be, have, do, and the modals) combine with main verbs to build questions, negatives, tenses, aspects, and passive voice.

Pattern: if you need to ask a question, negate, or stack tense/aspect — you need an auxiliary. The main verb carries meaning; the auxiliary carries grammar.

Clause

• I missed the bus. — ✅ independent clause (stands alone)
• Because I overslept. — ❌ fragment (dependent clause, can't stand alone)
• Because I overslept, I missed the bus. — ✅ dependent + independent = complete sentence
• I missed the bus, and I was late. — ✅ two independent clauses joined by and

A clause is a unit built around a verb with a subject. Independent = can stand alone. Dependent = needs an independent clause to complete it.

Test: does the group of words have a subject + verb AND can it be a sentence on its own? Yes → independent clause. Has a subject + verb but feels incomplete → dependent clause.

Complex sentence

• ✅ Because I overslept, I missed the bus. — dependent clause (reason) + independent
• ✅ The man who called is my uncle. — relative clause inside the sentence
• ✅ If it rains, we'll stay inside. — conditional dependent + independent
• ❌ Because I overslept. — fragment (dependent clause alone)

A complex sentence pairs an independent clause with one or more dependent clauses linked by subordinating conjunctions (because, although, if, when) or relative pronouns (who, which, that).

Pattern: independent clause = the main point. Dependent clause = the background, reason, or condition. Move the dependent clause around for emphasis.

Indirect speech

• Direct: "I am tired." → Indirect: She said she was tired. (present → past)
• Direct: "I will come." → Indirect: He said he would come. (will → would)
• Direct: "I have finished." → Indirect: She said she had finished. (present perfect → past perfect)
• today → that day; here → there; tomorrow → the next day

Indirect speech reports someone's words without quotation marks. The mechanism: backshift tenses one step into the past, shift pronouns, and adjust time/place expressions.

Rule: if the reporting verb is past (said, told, asked), shift the reported tense back one step. If the reporting verb is present (says), no shift needed.

Irregular verb

• ✅ go → went → gone — ❌ goed / goed
• ✅ eat → ate → eaten — ❌ eated / eated
• ✅ put → put → put — all three forms identical
• ✅ cut → cut → cut — no change group

Irregular verbs don't add -ed for past tense — they change form unpredictably. About 200 common English verbs are irregular, and they include the most frequently used verbs (be, have, go, do, say, make, take).

Pattern: no rule covers all of them. Some rhyme (sing/sang/sung, ring/rang/rung), some don't change (put/put/put), some are unique (go/went/gone). Memorisation is the only path.

Negation

• ✅ I don't see anything. — ❌ I don't see nothing. (double negative in standard English)
• ✅ She never goes out. — never already negates (no doesn't needed)
• ✅ He doesn't like coffee. — do-support for negation
• ✅ Nobody came. — negative subject (no auxiliary needed)

Negation uses not after an auxiliary/modal, or do-support when there's no auxiliary. One negative per clause in standard English — never, nobody, nothing already negate without adding not.

Rule: one negative element per clause. I don't see anything or I see nothing — never both together in standard English.

Object

• Sam fed the dogs. — direct object (what was fed)
• She sent him a present. — indirect object (who received it)
• She waited for Lucy. — prepositional object (after preposition)
• I gave her a book. — indirect + direct object together

An object is what a verb acts on or directs its action toward. Direct = the thing affected. Indirect = the recipient. Prepositional = after a preposition.

Test: Verb + what/whom? = direct object. Verb + to/for whom? = indirect object. After a preposition? = prepositional object.

Past tense

• I walked home. — simple past (completed action)
• I was walking when it rained. — past progressive (in progress)
• I had already left when she arrived. — past perfect (earlier past)
• I had been waiting for an hour. — past perfect progressive (duration up to a past point)

Four past tense forms: simple past (done), past progressive (was happening), past perfect (had already happened), past perfect progressive (had been happening). Each encodes different timing relative to other past events.

Pattern: simple past = the story's main timeline. Past progressive = background action. Past perfect = flashback to something even earlier.

Phrasal verb

• give up = quit — ≠ give + up literally
• come across = find by chance — ≠ come + across literally
• put up with = tolerate — 3-word phrasal verb
• look into = investigate — ≠ physically look inside something

Phrasal verbs = verb + particle/preposition forming a unit with non-literal meaning. There are thousands, and they dominate casual native English. They must be learned as whole units.

Key fact: the particle completely changes the verb's meaning. Look up (search), look after (care for), look into (investigate), look down on (disrespect) — all different.

Preposition

• ✅ interested in — ❌ interested on
• ✅ good at football — ❌ good in football
• ✅ depend on — ❌ depend of
• ✅ arrive at the station — ❌ arrive to the station

Prepositions link nouns to the rest of the sentence: time (at 5pm), place (in London), manner (with care), abstract (afraid of). Most are idiomatic — the "correct" preposition must be memorised with each verb/adjective combination.

Rule: there is no universal rule. English prepositions are learned by combination: interested IN, good AT, depend ON, afraid OF. Your native language's equivalent will often mislead.

Present tense

• I work here. — simple present (habit/permanent)
• I am working now. — present progressive (happening right now)
• I have lived here for 10 years. — present perfect (started past, still true)
• I have been waiting for an hour. — present perfect progressive (duration up to now)

Four present tense forms: simple (habits/facts), progressive (now/temporary), perfect (past → present relevance), perfect progressive (ongoing duration). Each encodes a different relationship between the action and the present moment.

Trap: "I am living here for 10 years" ❌ — started in the past + still true = present PERFECT (have lived/have been living), not progressive.

Pronoun

• ✅ between you and me — ❌ between you and I (objective case after preposition)
• ✅ its colour — ❌ it's colour (it's = it is)
• ✅ She did it herself. — reflexive pronoun
• ✅ The person who called… — relative pronoun

Pronouns replace nouns: personal (I/me/my), demonstrative (this/that), relative (who/which/that), interrogative (who?/what?), reflexive (myself), indefinite (everyone/nobody). They carry case that nouns have lost.

Trap: pronouns are where English case still matters: I vs me, who vs whom, its vs it's. Get these wrong and it's instantly noticeable.

Questions

• ✅ Do you like coffee? — do-support (no existing auxiliary)
• ✅ Can she swim? — inversion (auxiliary before subject)
• ✅ Where does he live? — wh-question
• ✅ You're coming, aren't you? — tag question

Questions require inversion (auxiliary before subject) or do-support (add do/does/did). Types: yes/no (Do you…?), wh- (What/Where/When…?), negative (Don't you…?), tag (…isn't it?).

Rule: find the auxiliary. Move it before the subject. No auxiliary? Add do/does/did. Never use just intonation in written English (You like coffee? is not standard).

Subject

• ✅ The list of items is wrong. — subject = list (singular), not items
• ❌ The list of items are wrong. — trapped by nearest noun
• ✅ Running is good exercise. — gerund as subject
• ✅ What he said surprised me. — clause as subject

The subject is the noun/pronoun/phrase before the verb that controls its number and person. Finding the true subject — especially through prepositional phrases — is the key to subject-verb agreement.

Rule: strip away prepositional phrases between subject and verb. Whatever's left is the true subject. The list (of items) is wrong.

Verb

• walk → walk / walks / walked / walked / walking (5 forms, regular)
• go → go / goes / went / gone / going (5 forms, irregular)
• be → am/is/are/was/were/be/being/been (8 forms)
• can → can / could (modal: only 2 forms, no -s, no -ing)

A verb is the one word class every English sentence requires. Carries tense (when), aspect (duration), mood (attitude), and voice (active/passive). Regular verbs add -ed; ~200 irregular verbs have unpredictable past forms.

Key insight: fix your verbs and most grammar problems disappear. Wrong tense, wrong agreement, wrong form — verb errors account for the majority of grammatical mistakes.

Verb tense

Verb tense = time (past/present/future) × aspect (simple/progressive/perfect) = 12 forms. Each slot has a specific job — not just "when" but "how the action relates to its time frame."

Key insight: most learners don't need all 12 at once. Simple covers 80% of communication. Add perfect and progressive as needed.

Perfect tense

• ✅ I have lived here for ten years. — present perfect (started past, still true)
• ❌ I live here for ten years. — wrong (simple present can't bridge past→now)
• ✅ She had finished before I arrived. — past perfect (earlier past)
• ✅ They will have left by noon. — future perfect (completed before future point)

The perfect = have + past participle. Connects an action to a reference point in time. Present perfect bridges past→now. Past perfect marks "earlier past." Future perfect marks "done before a future deadline."

Rule: if the action started in the past and is still relevant now → present perfect (have done). If two past events and you need the earlier one → past perfect (had done).

Progressive tense

• ✅ I am working in London. — temporary, happening now
• ✅ I work in London. — permanent/habitual (simple)
• ❌ I am knowing the answer. — stative verb, can't be progressive
• ✅ She was reading when I arrived. — past progressive (in progress at that moment)

The progressive = be + -ing. Marks actions as ongoing, temporary, or in-progress at a reference time. NOT used with stative verbs (know, believe, own, want, like) unless meaning shifts.

Rule: is the action temporary/in-progress right now? → progressive. Is it a permanent fact, habit, or schedule? → simple. Is it a stative verb? → almost never progressive.

Simple tense

• ✅ I go to work every day. — present simple (habit)
• ✅ She went home yesterday. — past simple (completed action)
• ✅ I will call you later. — future simple (promise/decision)
• ✅ Water boils at 100°C. — present simple (general truth)

The simple aspect is the default, unmarked verb form. Present simple = habits, facts, schedules. Past simple = completed actions. Future simple = predictions, promises, decisions. No auxiliary needed (except will for future and do for questions/negatives).

Rule: if the action is a fact, habit, completed event, or scheduled future — and you don't need to emphasise it being in-progress or connected to now → simple tense.

Word order

• ✅ She (S) eats (V) cake (O). — standard SVO
• ❌ Cake eats she. — SOV (not English)
• ✅ a lovely little old rectangular green French silver whittling knife — adjective order (opinion→size→age→shape→colour→origin→material→purpose)
• ✅ Never have I seen… — inversion after negative adverb

English word order = SVO (subject-verb-object) as default. Adjectives follow a fixed sequence (opinion→size→age→shape→colour→origin→material). Adverb placement varies by type. Deviations signal questions, emphasis, or literary style.

Rule: when in doubt, default to SVO. English position = meaning. Move a word and you change the grammar or the emphasis.

Collocations

• ✅ make a decision — ❌ do a decision
• ✅ strong coffee — ❌ powerful coffee
• ✅ heavy rain — ❌ strong rain
• ✅ highly unlikely — ❌ very unlikely (grammatical, but less natural)

Collocations are word pairs that English habitually puts together. Both options may be grammatically valid, but one sounds native and the other doesn't.

Pattern: there's no logic to predict them — you make decisions but do homework, you have strong coffee but heavy rain. They must be learned as chunks, not deduced from rules.

B1 | Intermediate

• ✅ If I had more time, I would travel more. — second conditional
• ✅ The bridge was built in 1920. — passive voice
• ✅ She said she was tired. — reported speech with backshift
• ✅ Although it rained, we enjoyed the trip. — complex sentence with concession

These are B1 patterns — the CEFR intermediate level. At B1 you link ideas, use passive voice, handle reported speech, and manage second conditional — enough for travel, work basics, and everyday independence.

Marker: if you can explain why something happened and follow a news story, you're B1.

B2 | Upper Intermediate

• ✅ If I had studied harder, I would have passed. — third conditional
• ✅ The report is being reviewed by the committee. — passive progressive
• ✅ Having finished the exam, she left. — participle clause
• ✅ He denied having taken the money. — complex verb pattern

These are B2 patterns — the CEFR upper-intermediate level. At B2 you handle mixed conditionals, all passive forms, participle clauses, and can argue a point clearly. This is the level most universities and employers require.

Marker: if you can write a structured essay and debate an abstract topic, you're B2.

Medium

• If I were you, I would apologise. — one rule (second conditional), but distractors like was tempt you
• Answers require active thought, not instant pattern recognition
• Vocabulary and context are realistic, not artificially simplified
• Usually tests one rule, but the wrong answers are plausible

Medium marks middle-difficulty challenges: A2–B1, one rule tested, but with realistic distractors that require genuine understanding.

Use "Medium" when Easy feels too obvious but Hard feels overwhelming. This is where most productive learning happens — the sweet spot of difficulty.