---May I play computer games now, Mum?---No, you ______. You’d better______. Music can make you relaxed!A.needn’t, to listen to musicB. mustn’t, listen to musicC. don’t have to, to listen to music
I think basketball is interesting, ______ he thinks it is ______.
— Let’s play _____ football. —That _____ good.
A set of keys ____ in the library. Are they yours?
— Where _______your books? — _______ in the bookcase
— Does David have a ping-pong ball? —________. But he has some tennis balls.