Relative Clauses: who, which, that, where

Relative clauses give extra information about a person, thing, or place.

They help you join two sentences into one sentence.

1. What is a relative clause?

A relative clause comes after a noun and gives more information about it.

Examples:

• Two sentences: "I have a friend. She lives in London."
  → One sentence: "I have a friend who lives in London."
• Two sentences: "This is a book. It is very interesting."
  → One sentence: "This is a book which is very interesting."

2. Who (people)

We use who for people.

Structure

Person + who/that + verb + (rest of clause)

Examples:

• "I have a friend who lives in London."
• "She is the teacher who helps me."
• "That is the man who called you."

Here, who is the subject (who = he/she).

Why?

The clause gives more information about a person.

3. Which (things)

We use which for things.

Structure

Subject relative: the relative pronoun is the subject inside the relative clause (it does the action). Example: "a thing which is very popular" (which = it).

Subject relative (who/which/that = the subject of the clause): thing + which/that + verb + (rest of clause).

Examples:

• "This is the book which is very interesting."
• "I have a phone which is very new."
• "That is the movie which we watched."

Why?

The clause gives more information about a thing.

4. That (people and things)

We can use that for people and things (instead of who/which).

With commas, the clause is extra information. Without commas, the clause tells us which person/thing we mean.

In these extra-information clauses, we use who/which (not that):

• "My brother, who lives in London, is a teacher." (extra information)

In needed-to-identify clauses (no commas), we can use that:

• "The teacher that helps me is kind." (necessary information)

5. Where (places)

We use where for places to mean 'in/at that place': 'the house where I live' (= 'the house (that) I live in').

Structure

place + where + clause (subject + verb + ...)

Examples:

• "This is the house where I live."
• "That is the restaurant where we ate."
• "I know a place where we can relax."

Why?

The clause gives more information about a place.

6. Subject vs object: when you can omit the relative word

Subject = the person/thing does the action.

Object = the person/thing receives the action.

If the relative word is the subject, you must use it:

• "The man who lives here is my teacher."

If it is the object, you can often omit it:

• "The book (that) I read is good." / "The book I read is good."

Do not omit it with where:

• "the place where I live" (not "the place I live")

7. Word order

This is the difference between subject and object relatives in word order:

• Subject relative: who/which/that + verb: "a man who works..."
• Object relative: who/which/that + subject + verb: "a phone which I bought..."

8. Easy way to remember

• who → people
• which → things
• that → people or things
• where → places

Use relative clauses to give more information:
who (people), which (things), that (people/things), where (places).