A non-defining relative clause adds extra, non-essential information about something already identified. It is always separated by commas, and that cannot be used: My sister, who lives in Paris, is a teacher.
Exercises:
Exercise 1 (Easy): Choose who or which
Choose the correct relative pronoun for the non-defining relative clause. Remember: 'that' is NOT used in non-defining clauses.
Exercises:
1
My sister, ___ lives in Paris, is visiting next week.
2
The Eiffel Tower, ___ was built in 1889, attracts millions of tourists.
3
My boss, ___ I respect a lot, gave me a promotion.
4
The new law, ___ was passed last month, affects everyone.
5
My grandfather, ___ was a sailor, travelled the world.
6
The film, ___ won three Oscars, is now on streaming.
7
London, ___ I visited last summer, is a wonderful city.
8
Her new novel, ___ took five years to write, is a bestseller.
9
Our neighbour, ___ is 90 years old, still goes jogging.
10
The report, ___ was written by the CEO, caused controversy.
Non-defining Relative Clauses
Extra information set off by commas, removable without changing the core meaning
Formula
Main clause+,+relative pronoun+extra info+,+rest
Key Rules
Always use commas to separate the clause.
Cannot use "that": use who, which, whose, where, when.
Can be removed without changing the sentence meaning.
Relative Pronouns (no "that")
whopeople
My sister, who lives in Paris, is a doctor.
whichthings
The film, which won an Oscar, is on TV.
whosepossession
My boss, whose office is huge, is strict.
whereplaces
Rome, where I lived, is beautiful.
whentimes
Last summer, when we met, was wonderful.
Defining vs Non-defining
DefiningNon-defining
CommasNo commasAlways commas
InformationEssentialExtra
thatOKNOT OK
Remove clause?Changes meaningSentence still fine
Examples
❌
My sister, that lives in Paris, is a doctor.
✅
My sister, who lives in Paris, is a doctor.
Quick test: If you can remove the clause and the sentence still makes complete sense, it's non-defining, so use commas.