Defining Relative Clauses
Learn how to use who, which, that, whose, where, and when to give essential information about a noun — and discover when you can drop the relative pronoun altogether.
Non-defining Relative Clauses
Learn how to add extra, non-essential information about a noun using who, which, whose, and when — always with commas, never with that.
Omitting the Relative Pronoun
Sometimes you can drop who, which, or that from a relative clause — and sometimes you absolutely cannot. After this guide you will know the difference instantly and use contact clauses naturally in both speech and writing.
Relative Pronouns
Choose the right pronoun to connect a relative clause to the noun it describes. After this guide you will know exactly when to use who, which, that, whose, and where — and when you can leave the pronoun out entirely.
Defining vs. non-defining relative clauses
Relative clauses modify nouns by adding information about them. English has two main types: defining (restrictive) clauses identify which item is meant ("The book that won the prize"), and non-defining (non-restrictive) clauses add extra information about an already-identified noun ("My sister, who lives in Paris, is a chef"). Non-defining clauses are set off by commas — omitting them changes the meaning.
The choice of relative pronoun depends on whether the antecedent is a person (who, whom) or a thing (which, that), and whether it functions as subject or object in the relative clause. In spoken and informal English, the relative pronoun is often omitted in object position ("The book [that] I read"), but this is not possible in subject position.
At B1, learners focus on basic who/which/that distinctions. At B2, non-defining clauses, whom, and reduced relative clauses (participle phrases) become important. At C1, learners handle cleft sentences, sentential relatives, and formal register distinctions.