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Help the eccentric biologist finish her field notes on a highly dramatic chameleon by choosing the correct word for each gap.
"The chameleon is truly fascinating; _________________________ ability to change color is unparalleled in the animal kingdom. However, _________________________ quite obvious that this particular lizard has completely forgotten _________________________ own camouflage mechanism, as _________________________ currently glowing bright pink while sitting on a dark green leaf."

The correct answers are its, it's, its, and it's.

Its (without an apostrophe) is the possessive form, meaning "belonging to it" (e.g., its ability, its own camouflage).

It's (with an apostrophe) is always a contraction for "it is" or "it has" (e.g., it's quite obvious, it's currently glowing).

Its' is never a real word in English!

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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.

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.

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.

Determiner

  • The cat sat on a mat. — articles as determiners
  • My sister has three dogs. — possessive + numeral as determiners
  • I went to the home. — wrong (idiomatic: I went home — no determiner)
  • She is a good student. ✅ vs She is good student. ❌ — missing determiner

A determiner sits before a noun to specify which, how many, or whose. Types include articles, demonstratives, possessives, and quantifiers.

Rule: most singular countable nouns in English require a determiner — a cat, the cat, my cat, this cat. Dropping it (cat sat on mat) breaks the sentence.

Punctuation

  • Period (.) — ends statements
  • Comma (,) — separates within sentences
  • Semicolon (;) — links related independent clauses
  • Colon (:) — introduces what follows
  • Question mark (?) — ends direct questions
  • Apostrophe (') — possession + contractions

Punctuation marks signal sentence structure to the reader: where thoughts end, how they connect, what's quoted, and what belongs to whom. ~12 marks, each with specific rules.

Key insight: punctuation isn't about pauses in speech. It's about grammatical structure. Learn the structure, and the punctuation follows.

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: A2B1, 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.