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Relative clauses: explanation and exercises

B1Updated 2026-09-216 exercises

A relative clause gives extra information about a noun. Who is used for people, which for things, that for either in defining clauses, whose for possession and where for places. Defining clauses identify which one we mean; non-defining clauses add extra detail and use commas.

How it is formed

Defining

The woman who lives next door is a nurse.

The book that I bought is great.

Non-defining

My sister, who lives in Denver, is a nurse.

Whose / where

A child whose parents work late.

The town where I was born.

When to use it

  • Identifying which person or thing you mean.
  • Adding detail without starting a new sentence.
  • Joining short sentences into fluent ones.

Common mistakes

  • Not thisThe man which lives here is kind.

    Say thisThe man who lives here is kind.

    Use who (or that) for people.

  • Not thisThe book what I read was good.

    Say thisThe book that I read was good.

    What is not a relative pronoun in this use.

  • Not thisMy sister, that lives in Denver, is a nurse.

    Say thisMy sister, who lives in Denver, is a nurse.

    Non-defining clauses cannot use that.

Tips for teaching it

  • Give two short sentences and have students join them: This is the boy. He won the race.
  • Ask whether the extra information is essential. If it is, no commas; if not, use commas.
  • Point out that the pronoun can often be dropped when it is the object: The book I bought is great.

Practice: relative clauses exercises

Try these exercises. Answers are checked in your browser and never sent to us. Teachers can share this page with a class as it is.

1Complete the sentence.

The womanlives next door is a nurse.

2Complete the sentence.

This is the bookI bought yesterday.

3Complete the sentence.

A childparents work late often stays at school.

4Complete the sentence.

The townI was born is very small.

Which sentence is correct?

Which clause needs commas?

Frequently asked questions

Can I use that instead of who or which?

Yes in defining clauses: the woman that lives next door. Never in non-defining clauses, which need who or which and commas.

When can the relative pronoun be left out?

When it is the object of its clause: the book (that) I bought. It cannot be left out when it is the subject: the woman who lives next door.