Relative Clauses: Who, Which, That, Where, Whose

Relative clauses add extra information about which person or thing. Pronouns: who (people), which (things), that (both, in defining clauses), where (place), whose (possession).

Defining (no commas)

You need the clause to know which one:

• The woman who called you is my boss.
• This is the book that I bought. — that/which as object can be dropped: the book I bought

Non-defining (commas)

Extra information; do not use that:

• Warsaw, which is the capital of Poland, is on the Vistula.
• My brother, who lives in Gdańsk, is a teacher.