Non-defining relative clauses help us add extra information about a person, place, or thing.
This information is not essential to understand the sentence. The clause contains an additional, interesting detail.
👉 We always use commas with non-defining relative clauses.
👉 We NEVER use “that” in non-defining clauses.
What Is a Non-Defining Relative Clause?
A non-defining relative clause:
- gives extra information
- is separated with commas
- uses relative pronouns like who, which, where, when, whose
- can be removed and the sentence still makes sense
How to Form Non-Defining Relative Clauses
Non-defining relative clauses give extra information about a person, place, or thing.
This information is not essential to understand the main idea.
We always use commas to separate the extra information.
1. Structure
Main clause, relative pronoun + extra information, rest of the sentence.
2. Common Relative Pronouns (for Non-Defining Clauses)
| Relative Pronoun | Used For | Example |
|---|---|---|
| who | people | My English teacher, who is from Canada, is very friendly. |
| which | things / animals | The book, which I finished yesterday, was fantastic. |
| where | places | Vancouver, where my cousins live, is beautiful. |
| when | times | 2010, when I finished high school, was an important year for me. |
| whose | possession | Anna, whose car broke down, arrived late. |
📝 Important:
Always add a comma before and after the clause (unless it ends the sentence).
Don’t use “that” in non-defining clauses.
3. Comma Rules
- Put a comma before and after the non-defining relative clause
(unless it’s at the end of the sentence; then you only need one comma).
4. Key Points for Low-Level Learners
- You can remove the extra information and the sentence still makes sense.
- The verb form inside the clause follows normal grammar rules.
- Do not use these clauses to identify someone/something.
(Those are defining clauses.)
Examples:
- My brother, who lives in Mexico, is visiting next month.
(extra info: he lives in Mexico) - The Eiffel Tower, which is in Paris, is very popular.
(extra info: its location) - September, when the weather is mild, is my favorite month.
(extra info: weather in September) - Chichén Itzá, where millions of tourists go each year, is amazing.
(extra info: visitors)
🧠 Compare: Defining vs. Non-Defining
| Type | Purpose | Example | Commas? | Use “that”? |
|---|---|---|---|---|
| Defining | Necessary information | The man who works here is kind. The man that works here is kind. | ❌ No | ✔ Yes |
| Non-defining | Extra information | My uncle Bob, who works here, is kind. | ✔ Yes | ❌ No |
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