— May we leave the classroom now?
— No, you . You to leave until the bell rings.
A. mustn’t; are allowed
B. can’t; aren’t allowed
C. don’t have to; are allowed
D. needn’t; aren’t allowed
网友回答
A. mustn’t; are allowed
(答案→)B. can’t; aren’t allowed
C. don’t have to; are allowed
D. needn’t; aren’t allowed
解析：may的否定回答应该用can’t，表示不能，不可以；而mustn’t表示禁止，一般不做否定回答；don’t have to表示不必；needn’t是must的否定回答，表示“不必”。所以本题选B。