Choose the correct word to complete the detective's dramatic courtroom revelation.
"Ladies and gentlemen of the jury, ___ the defendant hid inside that oversized tuba is exactly the missing diamond we've been searching for!"
The correct answer is what.
Here, what functions as a nominal relative pronoun (meaning "the thing that"). It acts simultaneously as the object of "hid" and as the head of the noun clause that serves as the subject of the main sentence. Using that would create a declarative fact ("The fact that he hid... is the diamond"), which makes no logical sense in this context!
Relative clause
- ✅ The man who called is my uncle. — restrictive (essential: which man?)
- ✅ My uncle, who lives in Paris, called. — non-restrictive (extra info, commas)
- ❌ My uncle that lives in Paris — wrong (that can't introduce non-restrictive)
- ✅ The book that I read = The book I read — restrictive (pronoun optional)
Relative clauses modify nouns using who/whom/whose/which/that or where/when/why. Restrictive = essential, no commas, that OK. Non-restrictive = extra, needs commas, uses which/who (never that).
Rule: if you can remove the clause and still know which noun is meant → non-restrictive (commas). If removing it makes the noun ambiguous → restrictive (no commas).
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.
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.
C2 | Proficiency
- ✅ His was a pyrrhic victory, if ever there was one. — literary allusion + inversion
- ✅ She'd have been none the wiser had he not let slip. — inverted conditional + idiom
- ✅ The proposal, laudable though it may be, fails on pragmatic grounds. — formal concession
- ✅ "Nice weather," he deadpanned, eyeing the hailstones. — irony + narrative register
These are C2 patterns — the highest CEFR level. At C2 you handle literary allusion, irony, any register, and complex written argument with native-like precision across all subjects.
Marker: if your English is indistinguishable from an educated native speaker's across registers, you're C2.
Hard
- Had she not intervened, the situation would have escalated. — inverted conditional
- All distractors are grammatically plausible in other contexts
- Multiple rules interact (e.g., tense + aspect + modality)
- Context determines the answer — no single "rule" is enough
Hard marks upper-intermediate to advanced challenges: B2+, interacting rules, edge cases, plausible distractors, and contexts where pattern-matching fails.
Use "Hard" when Easy/Medium feel trivial and you want to test whether you actually understand a rule versus just recognising surface patterns.