Defining relative clauses give us more information about a noun.
They answer the question: Which person? Which thing? Which place?
Defining relative clauses come immediately after the noun in the main clause.
Use who to talk about people, which to talk about things and where to talk about places:
- This is the book which you want.
- She's the teacher who I like.
- That's the shop where I bought these shoes.
That can be used instead of who or which:
- The young man that/who I work with never stops talking.
- Tom bought the jacket that/which we saw yesterday.
Don't use commas before or after defining relative clauses!