Defining and Non-defining Relative Clauses
Learn how to give additional information about people and things using relative clauses. Understanding the difference between these clauses is crucial – one gives essential information needed to identify someone/something, while the other just adds extra details.
⏰ When Do We Use These Clauses?
Defining Relative Clauses (No Commas):
To give essential information that identifies the person/thing
- The doctor who works at the city hospital is my cousin.
- Engineers that design buildings must be very precise.
Non-defining Relative Clauses (With Commas):
To give extra information that isn’t essential
- Dr. Smith, who has worked here for 20 years, is retiring.
- My sister, who is a lawyer, lives in London.
📌 Structure
Defining Clauses:
Who/That/Which + essential information
No commas
The teacher who speaks five languages works here.
Non-defining Clauses:
Comma(,) + Who/Which (never 'that') + extra information + Comma(,)
Use commas
My boss, who started the company, is retiring soon.
Common Relative Pronouns
For People:
- Who (defining and non-defining)
- That (only defining)
- Whom (formal, for objects)
For Things:
- Which (defining and non-defining)
- That (only defining)
📝 Notes
Common Mistakes:
- My uncle, that is a doctor, lives nearby.
- My uncle, who is a doctor, lives nearby.
- The dentist which I visited was excellent.
- The dentist who I visited was excellent.
Important Tips:
- Always use commas with non-defining clauses
- If removing the clause changes the meaning → Defining
- If removing the clause doesn’t change the meaning → Non-defining
- Never use ‘that’ in non-defining clauses
💬 Examples
Defining Clauses (Essential Information):
- The nurses who work in emergency care need special training.
- Teachers that work with young children need lots of patience.
- The chef who won the competition trained in Paris.
Non-defining Clauses (Extra Information):
- My brother, who is a successful architect, designed this building.
- Dr. Johnson, who graduated from Harvard, runs the department.
- The new manager, who moved here from Spain, starts next week.