Relative Clauses

Give additional information about nouns using who, which, that, where, when, whose

What are Relative Clauses?

Relative clauses give extra information about a noun. They start with relative pronouns (who, which, that, where, when, whose) or relative adverbs and help combine sentences and avoid repetition.

Example: "The woman" + "She lives next door" → "The woman who lives next door is a teacher."

Relative Pronouns

WHO - for people:

The man who called you is my brother.
She's the teacher who helped me.
I know someone who speaks five languages.

WHICH - for things/animals:

The book which I bought is excellent.
This is the car which won the race.
The dog which barks all night is annoying.

THAT - for people or things (informal):

The man that called you is my brother.
The book that I bought is excellent.
This is the best film that I've ever seen.

WHERE - for places:

This is the house where I grew up.
The restaurant where we met is closed now.
The city where she lives is beautiful.

WHEN - for times:

I remember the day when we first met.
Summer is the time when I'm happiest.

WHOSE - for possession:

The woman whose car was stolen called the police.
I met a man whose daughter is famous.
That's the house whose roof is red.

Defining vs. Non-Defining Relative Clauses

DEFINING (No Commas) - Essential Information:

The woman who lives next door is a doctor. (which woman? essential!)
I need a phone that has a good camera.
Students who study hard get good grades.
The book that you lent me was great.

NON-DEFINING (Commas) - Extra Information:

My sister, who lives in Paris, is a doctor. (extra info, I have one sister)
My phone, which cost $1000, is broken. (just adding detail)
London, where I was born, is expensive.
My father, who is 60 years old, still works.

Key Difference:

Defining: Tells us WHICH ONE. No commas. Can use "that."
Non-defining: Adds EXTRA INFO. Use commas. Cannot use "that" (use who/which).

Omitting the Relative Pronoun

Can omit when it's the OBJECT:

The book (that/which) I bought is great. (I bought IT - object)
The man (that/who) you met is my boss.
The film (that/which) we saw was boring.

Cannot omit when it's the SUBJECT:

The man who called is my boss. ✅ (HE called - subject)
❌ The man called is my boss. (wrong!)

Subject vs. Object Relative Pronouns

Subject (does the action):

The woman who lives here is nice. (she lives)
The car which crashed was red. (it crashed)

Object (receives the action):

The woman (who) I met was nice. (I met her - can omit)
The car (which) he bought was red. (he bought it - can omit)

Common Mistakes

❌ The man which called... → ✅ The man who/that called... (people = who/that)
❌ My sister, that lives in Paris, ... → ✅ My sister, who lives in Paris, ... (non-defining can't use "that")
❌ The place where I live there is... → ✅ The place where I live is... (no "there")
❌ The book who I read... → ✅ The book which/that I read... (things = which/that)
❌ She's the woman her car was stolen. → ✅ ...woman whose car was stolen.
❌ My father who is 60 is retired. → ✅ My father, who is 60, is retired. (need commas)

Practice Tips

👤 People vs. Things: WHO/THAT for people. WHICH/THAT for things. "The person who..." "The thing which..."
📍 Comma test: Can you remove the clause and still know which one? If yes, use commas (non-defining). If no, no commas (defining).
🚫 No double words: Don't use "there/it/him" after "where/which/who." "The place where I live" NOT "where I live there."
✂️ Omit when possible: If the pronoun is the object, you can often omit it in spoken English: "The book I read" (more natural than "which I read").
🔑 THAT restrictions: Cannot use "that" in non-defining clauses or after prepositions ("the person to whom I spoke" NOT "to that").