A defining relative clause identifies which person or thing we mean – without it the sentence is incomplete – and has no commas. A non-defining clause only adds extra information, is put between commas, and cannot use “that”. Commas change the meaning.
Form
| Structure | Example |
|---|---|
| defining: no commas, that allowed, pronoun can be dropped (object) | The man who called is my uncle. |
| non-defining: commas, no "that", pronoun required | My uncle, who lives in London, called. |
When to use it
- Defining: The students who passed got a certificate. (only some students)
- Non-defining: The students, who passed, got a certificate. (all of them)
- Non-defining with a name or unique noun: Mount Everest, which is 8,849 m high, attracts climbers.
- Whose and where work in both: a man whose son is a doctor.
- Which can refer to a whole clause: He passed, which surprised everyone.
Examples
- The woman who lives next door is a nurse.
- My sister, who lives in Berlin, is a nurse.
- The book that I borrowed was great.
- Paris, which is the capital of France, is beautiful.
- This is the house where I grew up.
- The students, who were tired, went home.
Common mistakes
- “That” in a non-defining clause: My car, that is old, broke down → which is old.
- Commas in a defining clause: The man, who called, is my uncle → no commas if it identifies him.
- Dropping the pronoun in a non-defining clause: My uncle, lives in London → who lives in London.