A defining relative clause tells us which person or thing we mean, so it is essential. It has no commas: “Pupils who are late must sign in.” Only the late pupils must sign in.
A non-defining clause adds extra information about something already identified. It goes between commas: “My bike, which is red, has a flat tyre.” Remove it and the sentence still works.
The commas change the meaning: “The students, who finished early, went home” means all of them finished early.
Worked example
Should there be commas? “My grandmother who lives in Ghana is eighty.” (I have only one grandmother.)
- With one grandmother, the clause does not identify which one.
- So it is extra information: use commas.
Answer:My grandmother, who lives in Ghana, is eighty.
Key words
- defining clause
- a relative clause that identifies which one
- non-defining clause
- a relative clause that adds extra information
- essential
- needed for the meaning
Practise this
New questions every time.
Common Core-referenced: L.6.2a