Relative Clauses — Defining vs Non-defining
Defining (restrictive) clause
- No commas The clause is essential to identify the person/thing.
- The students who arrived late missed the quiz. (Which students?)
- Pronouns allowed: who/that (people), which/that (things), whose (possession).
- Omission (zero pronoun) is possible when it is the object: The book (which/that) I bought.
Non-defining (non-restrictive) clause
- Between commas Adds extra information; the reference is already clear.
- My sister, who lives in Cardiff, is a vet.
- Use who/which/whose. Not that.
- No omission of the relative pronoun.
Choosing the relative word
| Refers to | Subject position | Object position | Possession / place / time / reason |
|---|---|---|---|
| People | who / that (defining) • who (non-defining) | who (informal) / whom (formal) / that (defining) | whose + noun: the man whose car… |
| Things/animals | which / that (defining) • which (non-defining) | which / that (defining) | whose or of which (formal): a film whose title… |
| Place / time / reason | where (= in/at which), when (= on/at which), why (= for which, usually after reason). | ||
⚠️ That is common in defining clauses, especially after all, everything, the only, the first, superlatives (the only book that…). It is not used in non-defining clauses or after a preposition placed before the pronoun.
Omission & prepositions
- Omit the pronoun only when it is the object: The people (who/that) we met…
- Keep it for subjects and after prepositions.
- Preposition at the end (neutral): the person who I spoke to.
- Preposition before the pronoun (formal): the person to whom I spoke. (Use whom/which, not that.)
which referring to a whole clause
- Use non-defining which to comment on the previous idea: He missed the last train, which was unlucky.
- Do not use that here.
Reduced relative clauses (B1+ handy)
- Present participle (active meaning): Students taking the exam must switch off phones. (= who are taking)
- Past participle (passive meaning): Items left on the bus will be donated. (= that are left)
- Used only for defining information (no commas).
Common mistakes to avoid
- Two subjects: ✖ the man who he lives next door → ✔ the man who lives…
- That with commas: ✖ My car, that I bought last year, … → ✔ My car, which I bought last year, …
- Using what as a relative pronoun: ✖ the book what I liked → ✔ the book (that/which) I liked. (what = “the thing that” with no antecedent: I like what you did.)
- Whose for people and things: ✔ a company whose products…
Punctuation: put commas only around non-defining clauses. Defining clauses take no commas.
Exercises:
Defining and non-defining relative clauses
Choose the correct relative pronoun or adverb for the following defining and non-defining relative clauses.
1
My brother,
now lives in Tokyo, speaks three languages.
2
The book
I borrowed from you was fascinating.
3
I’d like to go back to the café
we first met.
4
She interviewed the scientist
research changed the field.
5
2010 was the year
our startup launched.
6
Our flight,
was delayed by storms, finally took off at midnight.
7
The reason
I called is to invite you.
8
The manager to
you complained will contact you.
9
The town
I grew up has changed a lot.
10
Her latest album,
was recorded in Paris, topped the charts.
Defining and non-defining relative clauses
Choose the correct relative pronoun or adverb for the following defining and non-defining relative clauses.
1
This is the café _____ we met for the first time.
A.
B.
C.
2
That’s the man _____ daughter won the lottery.
A.
B.
C.
3
My brother, _____ lives in Sydney, is coming to visit.
A.
B.
C.
4
The film _____ we watched last night won three awards.
A.
B.
C.
5
2010 was the year _____ I moved to Italy.
A.
B.
C.
6
The reason _____ she left early was a family emergency.
A.
B.
C.
7
Our office, _____ has only ten employees, won the contract.
A.
B.
C.
8
The teacher _____ you emailed will reply tomorrow.
A.
B.
C.
9
That’s the house _____ roof collapsed in the storm.
A.
B.
C.
10
Madrid, _____ I lived for two years, will always feel like home.
A.
B.
C.
Defining and non-defining relative clauses
Fill in the gaps with who, which, whose, where, or when.
1
The scientist discovered the treatment won a major award.
2
The museum, opened last year, is free on Sundays.
3
Can you give me back the book you borrowed from me?
4
Is that the café we met for the first time?
5
Do you remember the summer we travelled around Italy?
6
My cousin, lives in Dublin, has just got married.
7
The singer album won a Grammy is from our town.
8
2010 was the year the volcano erupted in Iceland.
9
Their car, was stolen last week, has been found by the police.
10
Do you know anyone can repair vintage cameras?