Adjective clauses
An adjective clause (also called a relative clause) is a group of words containing a subject and verb that describes a noun or pronoun in a sentence. It usually begins with a relative pronoun (who, whom, whose, which, that) or relative adverb (where, when, why) and answers questions like "which one?" or "what kind?"
Types of adjective clauses
Restrictive (defining) adjective clauses
These give essential information needed to identify the noun; removing them changes the sentence's meaning, and no commas are used.
e.g. The book that I borrowed is overdue., Students who study regularly perform better.
Non-restrictive (non-defining) adjective clauses
These add extra, non-essential information about a noun that is already identified; they are set off with commas and can be removed without changing the core meaning.
e.g. My father, who is a doctor, works long hours., Paris, which is the capital of France, attracts millions of tourists.
Clauses with relative adverbs
These begin with where, when or why and describe nouns related to place, time or reason.
e.g. This is the house where I grew up., I remember the day when we first met.
Clauses with omitted relative pronoun
The relative pronoun (that, which, whom) can be dropped when it is the object of the clause, common in informal speech and writing.
e.g. The movie (that) we watched was boring., She is the woman (whom) I met yesterday.
Rules to remember
- An adjective clause must contain a subject and a verb, and it always modifies a noun or pronoun that comes immediately before it.
- Use who/whom for people, which for things, that for people or things, and whose to show possession.
- Restrictive clauses use no commas; non-restrictive clauses require commas to separate them from the main clause.
- Do not use 'that' to introduce a non-restrictive clause; use 'which' or 'who' instead.
- The relative pronoun can be omitted only when it functions as the object of the clause, never when it is the subject.
Examples in sentences
| Example | How it works |
|---|---|
| The woman who called earlier left a message. | Restrictive clause identifying which woman; no commas needed. |
| My car, which I bought last year, needs a repair. | Non-restrictive clause adding extra detail; set off with commas. |
| This is the restaurant where we celebrated our anniversary. | Relative adverb 'where' introduces a clause describing a place. |
| The man whose wallet was stolen called the police. | 'Whose' shows possession linking the man and the wallet. |
| The report that I submitted yesterday was approved. | 'That' introduces a restrictive clause describing 'the report'. |
| She thanked the teacher who had helped her. | 'Who' refers to a person and functions as the subject of the clause. |
| The gift (which) he gave me was thoughtful. | The object relative pronoun 'which' can be omitted informally. |
Common mistakes
Incorrect: My sister who lives in Canada, is visiting us.
Correct: My sister, who lives in Canada, is visiting us.
Incorrect: The car that, I bought last week broke down.
Correct: The car that I bought last week broke down.
Incorrect: This is the man which helped me.
Correct: This is the man who helped me.
Why this matters for IELTS
Using adjective clauses accurately allows IELTS candidates to combine short, simple sentences into longer, more sophisticated ones, which directly boosts the Grammatical Range and Accuracy score in both Writing and Speaking. Examiners look for a mix of complex sentence structures, and correctly punctuated restrictive and non-restrictive clauses show control over subordination. Overusing 'which' incorrectly or forgetting commas, however, can create errors that lower accuracy, so practising the punctuation rules is essential before test day.
Frequently asked questions
What is an adjective clause in simple terms?
It is a clause, containing a subject and verb, that describes a noun, similar to how a single adjective would, usually starting with words like who, which or that.
What is the difference between an adjective clause and an adjective phrase?
An adjective clause has its own subject and verb (e.g. 'who lives here'), while an adjective phrase lacks a verb and simply adds description (e.g. 'living here').
Can you start a sentence with an adjective clause?
No, an adjective clause cannot stand alone or begin a sentence because it is dependent; it must directly follow the noun it modifies within a main clause.
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