- (relative) You use who to add a clause to explain more about the person or people you're talking about.
- They are good people who are working hard.
- We saw Kim, who was in his car.
- We asked everybody who was there.
- It was you who lost the keys, not me.
- (question) You use who to ask about a person or people.
- Who was on the phone?
- Who's your new teacher?
- Who did you meet today?
- He told me who was there.
- I'll ask who can help us.