B1 Intermediate Relative clauses
Non-defining relative clauses
Lesson goal. After this lesson you can use relative clauses with commas to add extra information, and you understand how the comma changes the meaning.
When to use it
- Adding optional information about an already identified person or thing: My father, who is 50, still plays football.
- Adding detail about places and names: Ha Long Bay, which is in Quang Ninh, is beautiful.
- Common in formal writing and reading texts.
Form
| Feature | Defining | Non-defining |
|---|---|---|
| Commas | no | yes, at both ends |
| Using that | allowed | not allowed |
| Leaving out the pronoun | allowed (when it is the object) | not allowed |
| Remove the whole clause | the sentence loses meaning | the sentence still makes sense |
Step by step
- Ask: does the listener already know which one you mean?
- Yes (a name, my father, my car) → use a non-defining clause with commas.
- Choose who for people, which for things — never that.
- Put the extra information between two commas.
The comma changes the meaning
| Sentence |
|---|
| My brother who lives in Hue is a doctor. |
| My brother, who lives in Hue, is a doctor. |
| The students who passed were happy. |
| The students, who passed, were happy. |
Examples
My father, who is fifty, still plays football.
Ha Long Bay, which is in Quang Ninh, is very beautiful.
Ms Lan, who teaches us maths, is very patient.
This dictionary, which I bought last year, is very useful.
Nam, whose father is a doctor, wants to study medicine.
My car, which is ten years old, still works well.
Common mistakes
My sister, that lives in Hue, is a nurse. → My sister, who lives in Hue, is a nurse.
Never use that after a comma. This is the clearest difference between the two clause types.
Lan, who she sits next to me, is very funny. → Lan, who sits next to me, is very funny.
who is already the subject; drop she.
My father who is fifty still plays football. → My father, who is fifty, still plays football.
Without commas the sentence implies you have several fathers. Extra information about an identified person needs commas.
Memory tip
Try deleting the clause. If the sentence still makes sense and you still know who is meant → use commas. If it becomes vague → no commas.
Summary
- Non-defining clauses take commas and only add information.
- Never that, and the pronoun cannot be dropped.
- The comma changes the meaning: with it the thing is unique, without it you are singling one out.
Practise this lesson
Do exercises with an explanation for every question, take mini tests and track your progress on GrammUp.