---May we leave the classroom now?
---No, you . You to leave until the bell rings.
A. mustn’t, are allowed
B. don’t have to, are supposed
C. needn’t, aren’t allowed
D. can’t, aren’t supposed
网友回答
A. mustn’t, are allowed
B. don’t have to, are supposed
C. needn’t, aren’t allowed
(答案→)D. can’t, aren’t supposed
解析：句意：我们现在可以离开教室吗？不，你们不能，直到下课铃响了，才可以离开。can’t表示不能够，用于回答may的提问，be supposed to do sth应该做某事，故选D