— Must we wear our school uniform this afternoon?— No, you. All of us will go on an outing

网友回答

A. mustn't
B. can't
(答案→)C. needn't
D. couldn't
解析：mustn't禁止；can't不能，不可能；needn't不必；couldn't不能。句意：我们必须今天下午穿上我们的校服吗？——不，你们不必。我们都要去郊游。must的含义是必须一定，其否定形式mustn’t表示禁止的含义。故must的否定回答一般借助于needn’和don’t have to来构成，结合语境可知选C.