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.

Possessive

• ✅ its tail — ❌ it's tail (it's = it is, not possessive)
• ✅ the students' essays — plural possessive (apostrophe after the s)
• ✅ Sarah's book — singular possessive ('s)
• ✅ a friend of mine — possessive pronoun (not my)

Possessives show ownership: nouns use 's (singular) or s' (plural ending in s). Pronouns have special forms: my/mine, your/yours, his, her/hers, its, our/ours, their/theirs.

Trap: its (possessive) vs it's (= it is). Possessive pronouns NEVER use apostrophes — that's the opposite of nouns.

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.

Vocabulary

• A1: ~500–800 words (survival: family, food, numbers)
• A2: ~1,500–2,500 (routine: work, leisure, basic phrasal verbs)
• B1: ~2,500–4,000 (opinions, news, abstract topics)
• B2: ~4,000–6,000 (register precision, hedging, idioms)
• C1: ~6,000–10,000 (academic, register sensitivity)
• C2: 10,000+ (literary, rare, full style range)

Vocabulary covers word-level practice: individual words, collocations, phrasal verbs, idioms. Organised by CEFR level. Grammar tells you HOW to build sentences; vocabulary gives you WHAT to put in them.

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.

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.