Relative clauses: who, that, which

We can use relative clauses to join two sentences or to provide more information about something.

Defining and non-defining

A defining relative clause tells which noun we are talking about:

  • I like the woman who lives next door.

A non-defining relative clause gives us extra information about something. We don’t need this information to understand the sentence.

  • I live in London, which has some fantastic parks.

Commas

Deciding whether to use a comma before which, where, or who means determining the function of the relative clause.

  • When the information that follows the relative pronouns is essential to the sentence, you do not use a comma.

  • When the information is extra and the sentence is clear without it, you put a comma before the relative pronoun.

  • When the nonessential relative clause is in the middle of the sentence, the comma goes before the relative pronoun and after the clause.

  • When the nonessential relative clause is at the end of a sentence, only put a comma before the relative pronoun.

Examples

  • I want to eat at a restaurant where they serve sushi. (The sentence does not make sense without where they serve sushi because it clarifies what type of restaurant it is.

  • My dog, who loves to play fetch, is a Scottish terrier. (Who loves to play fetch is not crucial to the sentence. You can take it out and the sentence still makes sense.)

  • There was a tornado, which was strange for November.