Apostrophe

• ✅ the dog's bone (possession) — ❌ the dog's are barking (wrong — plural, no apostrophe)
• ✅ it's raining (= it is) — ❌ the cat licked it's paw (wrong — possessive its has no apostrophe)
• ✅ don't, they're, we'll (contractions) — ❌ apple's for sale (wrong — plain plural)
• ✅ James's book or James' book — both accepted for names ending in s

The apostrophe ( ' ) marks either possession (the eagle's feathers) or missing letters in contractions (do not → don't). It never makes a plural.

Rule: if you mean "belongs to," add 's. If you're shortening two words into one, apostrophe replaces the missing letters. Otherwise — no apostrophe.

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.

Imperative mood

• ✅ Sit down. — command (bare verb, no subject)
• ✅ Don't touch that. — negative imperative
• ✅ Let's go. — first-person inclusive imperative
• ❌ You sit down. — adding you sounds aggressive (only for emphasis/anger)

The imperative mood uses the bare verb form with no stated subject for commands, instructions, requests, and invitations. Negated with don't. Softened with please or replaced by questions (Could you…?) for politeness.

Rule: imperative = base form of verb, no subject, no tense marking. If there's a subject or tense → it's not imperative.

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.

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.

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.

A1 | Elementary | Beginners

• ✅ My name is Anna. — present simple of be
• ✅ Where is the station? — basic *wh-*question
• ✅ I have two brothers. — possession with have
• ✅ She likes coffee. — third-person -s

These are A1 sentences — the starting level of the CEFR framework. At A1 you can introduce yourself, ask and answer simple personal questions, and handle basic everyday transactions using present tense, be/have/do, and core vocabulary.

If you can say these but freeze at normal speaking speed, you're solidly A1 — and that's exactly where to start.

A2 | Elementary | Pre-intermediate

• ✅ I went to the cinema yesterday. — past simple
• ✅ I have visited Paris twice. — present perfect (life experience)
• ✅ If it rains, I'll take an umbrella. — first conditional
• ✅ You should see a doctor. — modal for advice

These patterns are A2 — the second CEFR level. At A2 you move past survival phrases into real grammar: past tenses, the present perfect, basic conditionals, and modals for advice/obligation.

Marker: if you can describe yesterday and give simple advice, but struggle with abstractions or nuance, you're at A2.

Easy

• She is a teacher. — one verb form, one rule
• I have two cats. — basic possession, short sentence
• He doesn't like coffee. — simple negation with do-support
• Only one answer is clearly correct; distractors are obviously wrong.

Easy marks beginner-level challenges: A1–early A2, one rule at a time, everyday vocabulary, no trick questions.

Use "Easy" when you want to build confidence on a specific rule without interference from other grammar or tricky contexts.