slug: relative-clauses title: Relative Clauses group: structures order: 7 summary: Add information about a noun using who, which, or that to introduce a relative clause. formula: Noun + who/which/that + S + V

When to use it

A relative clause follows a noun and gives more information about it. It is introduced by a relative pronoun — who, which, that, whose, or where. There are two types: defining (necessary to identify the noun) and non-defining (extra information, set off by commas).

The woman who lives next door is a doctor. (defining — tells us which woman) My sister, who lives in Hanoi, is visiting this week. (non-defining — extra info)

Form

In defining clauses, the relative pronoun can often be omitted when it is the object of the clause: "The book (that) I read was fascinating."

Examples

• The colleague who helped me with the project got a promotion.
• He lives in a house that was built over 100 years ago.
• This is the café where we had our first meeting.

Common mistakes

• Using that in non-defining clauses: "My mother, that lives in Hanoi, called me" → My mother, who lives in Hanoi, called me.
• Forgetting the comma in non-defining clauses: "My father who is 60 loves fishing" is ambiguous — if you have one father, add commas: My father, who is 60, loves fishing.
• Double subject: "The woman who she helped me" → The woman who helped me.