Defining Relative Clauses with Who, Which, That
Defining relative clauses are English's precision tools for identification, allowing you to specify exactly which person, thing, or place you're talking about without using separate sentences. These essential clauses provide crucial information that identifies or defines the noun they modify, making your communication more specific, efficient, and sophisticated.
Formed with relative pronouns like who, which, and that, defining relative clauses attach directly to nouns and become an integral part of the sentence structure. Unlike non-defining clauses, they don't use commas because the information they provide is essential for understanding which specific thing you mean. They answer the question "which one?" by giving identifying details.
What makes defining relative clauses particularly powerful is their ability to combine multiple ideas into single, flowing sentences whilst maintaining clarity. Instead of saying "I met a woman. The woman spoke five languages," you can elegantly combine these thoughts: "I met a woman who spoke five languages." This creates more sophisticated and natural-sounding English.
Mastering defining relative clauses will transform your English from basic, choppy sentences to smooth, professional communication. They're essential for describing people's qualities, explaining what things do, and identifying specific items amongst many possibilities, making your speech and writing sound more natural and fluent.
Formation
Structure
Main clause + relative pronoun + defining information
The relative clause provides essential information to identify the noun
Who (for people):
- The teacher who lives next door is very kind.
- Students who study hard get better results.
- Anyone who wants tickets should book early.
Which (for things):
- The book which you lent me was brilliant.
- Cars which use less fuel are popular.
- The house which we visited was for sale.
That (for people/things):
- The man that called you has left a message.
- The film that we saw was incredible.
- Everything that you need is here.
Subject vs Object Relative Pronouns
Subject (performs action):
The woman speaks French. She lives here.
The woman who lives here speaks French.
The car broke down. It was very old.
The car that was very old broke down.
Object (receives action):
I met a woman. You recommended her.
I met the woman (who) you recommended.
The book was brilliant. I read it.
The book (that) I read was brilliant.
Common Mistakes to Avoid
❌ "The man, who called you, has left."
✅ "The man who called you has left."
Don't use commas with defining relative clauses - the information is essential
❌ "The book what I read was brilliant."
✅ "The book that I read was brilliant."
Use 'that', 'which', or omit the pronoun - never use 'what' in relative clauses
❌ "The woman who she lives next door is kind."
✅ "The woman who lives next door is kind."
Don't repeat the subject with a pronoun after the relative pronoun
❌ "The people which work here are friendly."
✅ "The people who work here are friendly."
Use 'who' for people, 'which' for things, or 'that' for both
When You Can Omit Relative Pronouns
Object pronouns can be omitted:
The book (that) I read was brilliant.
The woman (who) you met is my sister.
The car (which) we bought is reliable.
Everything (that) you said was true.
Subject pronouns cannot be omitted:
The woman who lives next door is kind. (Cannot omit 'who')
The car that broke down was old. (Cannot omit 'that')
Choosing Between That, Which, and Who
Who:
- Only for people
- Subject or object
- More formal than 'that'
- Cannot be omitted when subject
Which:
- Only for things
- Subject or object
- More formal than 'that'
- Required in non-defining clauses
That:
- People or things
- More informal/spoken
- Preferred after superlatives
- Never in non-defining clauses
Defining vs Non-defining: Quick Comparison
Defining (Essential Information):
- No commas
- Identifies which one
- Cannot be removed
- Can use 'that'
"The student who studies hard will succeed."
Non-defining (Extra Information):
- Uses commas
- Adds extra information
- Can be removed
- Cannot use 'that'
"My brother, who lives in Spain, is a teacher."
Quick Reference Guide
Remember:
- Purpose: Identify which specific person or thing you mean
- Commas: Never use commas with defining relative clauses
- Essential: The information cannot be removed without changing meaning
- Pronouns: who (people), which (things), that (both)
- Omission: Object pronouns can be omitted in informal speech
- Subject: Relative pronouns as subjects cannot be omitted
- Position: Comes immediately after the noun it modifies