Non-defining relative clauses
Extra information between commas: my brother, who lives in Oslo, is a doctor. No that, and which for a whole sentence.
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A non-defining relative clause adds extra information about a person or thing that is already clear. Without it, the sentence still tells us who or what we mean. It has commas around it, and it starts with who, which, whose, where or when, but not that: My brother, who lives in Oslo, is a doctor.
Defining or non-defining?
A defining clause, which you met at B1, tells us which one we mean. A non-defining clause tells us something more about a person or thing we have already identified. The commas show the difference.
- My sister who lives in London is a nurse.
(I have more than one sister. I mean the one in London.)
- My sister, who lives in London, is a nurse.
(I have one sister. By the way, she lives in London.)
- Incorrect: My father who is seventy still plays tennis every week.
- Correct: My father, who is seventy, still plays tennis every week.You have only one father, so the clause can't tell us which one. It is extra information and needs commas.
Names, people like my mother, and things that are unique are usually followed by a non-defining clause: Moscow, which is the capital of Russia, ...
Commas: two or one
Put a comma before the clause, and another after it if the sentence continues. If the clause ends the sentence, the full stop does the work of the second comma. In speech, you hear a short pause instead.
- Our neighbours, who moved here last year, are from Spain.
- I gave the keys to Ivan, who was waiting outside.
Who, which, whose, where, when, but not that
Use who for people, which for things, whose for possession, where for places and when for times. In standard English, that is not used in a non-defining clause.
- Incorrect: My brother, that lives in Minsk, is a teacher.
- Correct: My brother, who lives in Minsk, is a teacher.With commas, use who for a person, not that.
- Incorrect: The museum, that opened in 2019, is free on Sundays.
- Correct: The museum, which opened in 2019, is free on Sundays.
- Kazan, where my parents live, is on the Volga.
- In 2015, when we moved here, the area was very quiet.
- The director, whose new film won a prize, gave a short speech.
Whom is the formal object form: Professor Lee, whom I met at the conference, ... In everyday English, who is normal there too.
You can't leave out the relative word
In a defining clause, an object who, which or that can be left out. In a non-defining clause it must stay.
- Incorrect: The new bridge, they opened last week, is already closed for repairs.
- Correct: The new bridge, which they opened last week, is already closed for repairs.A non-defining clause always starts with its relative word.
Which for a whole sentence
Which can refer back to the whole of the first part of the sentence, not just one noun. This is always non-defining, so it has a comma.
- He didn't call me back, which was strange.
- She passed all her exams, which surprised everyone.
- The train was cancelled, which meant we had to take a taxi.
- Incorrect: He forgot my birthday again, what really annoyed me.
- Correct: He forgot my birthday again, which really annoyed me.To refer back to a whole sentence, use which, not what.
Some of which, all of whom
After words like some, many, most, all, none, both and neither, use of which for things and of whom for people.
- I have three brothers, all of whom live abroad.
- She gave me two books, neither of which I have read.
- There were thirty people at the meeting, most of whom I didn't know.
- Incorrect: I've got two cousins, both of who are doctors.
- Correct: I've got two cousins, both of whom are doctors.After of, the form for people is whom.
Writing and speech
Non-defining clauses are much more common in writing. In conversation, people often use two sentences or and: My brother lives in Oslo. He's a doctor.
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Where this rule sits
All B2 rulesClauses and linking words: all rules