You are talking to your friends.
1 Are you talking to your friends?
2 You are talking to your friends, aren't you?
3 Are you talking to your friends or your parents?
4 Who is talking to your friends?
5 With whom are you talking?
They sang at the concert yesterday.
1 Did they sing at the concert yesterday?
2 They sang at this concert yesterday, didn't they?
3 Did they sing at the concert or restaurant yesterday?
4 Who sang at the concert yesterday?
5 What did they do yesterday?