Advanced … min read · Updated 2026-06-20

Complex Sentences: Adjective (Relative) Clauses

The second kind of dependent clause is the adjective clause (also called a relative clause) — it functions as an adjective, modifying a noun or pronoun. It begins with a relative pronoun: who/whom (people), which (things), whose/that (people or things), when (time), where (place).

Place the adjective clause as close as possible to the noun it modifies: The experiment that was carried out on the mouse was unsuccessful (clear) — not The experiment on the mouse that was carried out… (unclear).

Relative clauses are of two kinds:

KindRoleCommas?
Restrictive (defining)identifies the noun — essentialno commas
Non-restrictive (non-defining)adds extra, non-essential informationcommas

Restrictive: The material which was used in the experiment was impure. (needed to identify which material)

Non-restrictive: The material from the experiment, which was impure, was weighed twice. (extra detail — can be removed)

Tip: If you can remove the clause without losing the noun's identity, it is non-restrictive — set it off with commas. If removing it leaves the noun unclear, it is restrictive — no commas.

Common mistake: Putting the adjective clause far from its noun, creating ambiguity. Keep it next to the noun it describes.

✏️ Test Yourself

1. "The material, which was impure, was weighed twice."

2. "The material which was used in the experiment was impure."

3. Non-restrictive clauses are set off with ___ .

4. An adjective clause should sit close to the ___ it modifies.

📒 Words to learn

Replete (adj)

MeaningFilled to satisfaction.

Synonyms: Full, Packed

The meal was replete with flavors from various cuisines.

Vitiate (v)

MeaningCorrupt morally or impair the quality of something.

Synonyms: Corrupt, Spoil

The evidence was vitiated by the lawyer's improper conduct.

Hoax (n)

MeaningSomething intended to deceive.

Synonyms: Trick, Fraud

The rumor about the alien sighting turned out to be a hoax.

Prevail (v)

MeaningBe larger in number, power, or influence.

Synonyms: Triumph, Dominate

Justice will always prevail over evil.

Rogue (n)

MeaningA deceitful and unreliable scoundrel.

Synonyms: Scoundrel, Villain

The rogue managed to escape the authorities once again.

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