Grammar · Clauses, Connectors & Sentence Style
Non-Defining Relative Clauses
Add extra information with who and which, between two commas, with the film Brooklyn.
Grammar › Clauses, Connectors & Sentence Style › Non-Defining Relative Clauses
The rule in one sentenceTo add extra information between commas, use who for people and which for things and places – and never use “that” here.
About the film
Brooklyn is a film from 2015 about Eilis Lacey, a young woman from a small town in Ireland in the 1950s. With help from Father Flood, who is an Irish priest in New York, she moves to Brooklyn to find work. Eilis, who has only just arrived, misses home badly, and she lives in Mrs Kehoe’s house, which is full of young Irish women.
What does it do?
Sometimes you want to add a small extra fact to a sentence. You can put it in the middle or at the end, between commas. The sentence is complete without it. The extra part just gives more detail.
Start the extra part with who when you talk about a person. Start it with which when you talk about a thing or a place. Never use that after a comma like this.
Cover the part between the commas in the first tile: Eilis moves to Brooklyn. The sentence still works. The who part only adds a fact about Eilis.
Eilis lives in Mrs Kehoe’s house. The house is full of young Irish women.
→ Eilis lives in Mrs Kehoe’s house, which is full of young Irish women.
Two short sentences become one. The part after the comma is extra information.
Visual guide
Teacher Teddy’s illustrated guide to this rule is being drawn — the full swipe-through infographic will appear here soon.
How to make it
who — extra facts about people
Eilis, who is quiet and shy, starts a new job.
Eilis, who doesn’t know anyone, feels lonely.
The extra part can be negative too.Do you know Saoirse Ronan, who plays Eilis?
At the end of a sentence, one comma is enough.which — extra facts about things and places
Brooklyn, which is part of New York, is full of new people.
Her town, which doesn’t have many jobs, is in Ireland.
Have you seen Brooklyn, which came out in 2015?
When to use each one
who — people
which — things and places
Words that help: person or thing?
Look at the word just before the comma. It tells you which word to use.
who → a person
which → a thing or place
Common mistakes
❌ Eilis, that is from Ireland, moves to Brooklyn.
✅ Eilis, who is from Ireland, moves to Brooklyn.
Never use “that” after a comma. For people, use who.
❌ Brooklyn which is part of New York feels far from home.
✅ Brooklyn, which is part of New York, feels far from home.
The extra part needs a comma before it and after it.
❌ Tony, which is Italian-American, meets Eilis.
✅ Tony, who is Italian-American, meets Eilis.
Tony is a person, so use who.
❌ The letters, Rose writes, make Eilis sad.
✅ The letters, which Rose writes, make Eilis sad.
You can’t leave out who or which in this kind of sentence.
One more thing
This part is a little harder. You can come back to it later.
Whose means “his”, “her” or “their” in the extra part. And without commas, the meaning changes: the clause tells you which person you mean.
✅ Eilis, whose sister stays in Ireland, writes home often. (her sister)
✅ The women who live with Eilis are all Irish. (no commas – it tells you which women)
For the no-comma type, see the Defining Relative Clauses lesson.
Practice: who or which?
Eight questions. Choose one answer. You get the answer, and why.
1. Eilis, ___ is from Ireland, moves to Brooklyn.
Eilis is a person → who.
2. Brooklyn, ___ is part of New York, is very busy.
Brooklyn is a place → which.
3. Tony, ___ is Italian-American, meets Eilis at a dance.
Never use “that” after a comma. Tony is a person → who.
4. Which sentence has the right commas?
The extra part needs a comma before and after.
5. The letters, ___ Rose writes, make Eilis sad.
You can’t leave out which here.
6. Mrs Kehoe’s house, ___ has a lot of rules, is in Brooklyn.
A house is a thing → which.
7. Eilis, ___ sister stays in Ireland, writes home often.
Her sister → whose. Who’s means “who is”.
8. Father Flood, ___ is a priest, helps Eilis.
Father Flood is a person → who.
Your turn
Choose one ending. Then listen to your sentence.
Every sentence here is correct. Pick the one that is true for you. Say it out loud too!
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