Make a question for the phrase "his friends"

1.Peter goes to the cinema with his friends. (Make a question for the phrase "his friends")
2.My father gave up smoking three years ago. -> My father ____ . (Rewrite the sentences using the structure "used to V)
3.We often went to school by bike when we were young. -> We ____ . (Rewrite the sentences using the structure "used to V)
4.I often listen to folk music to relax. (Make a question for the phrase "to relax")