--- we clean the classroom at once?
---No, you . You clean it after school
A. Must, needn’t, can
B. Need, mustn’t ,may
C. Must, mustn’t, can
D. Shall, can’t , may
网友回答
(答案→)A. Must, needn’t, can
B. Need, mustn’t ,may
C. Must, mustn’t, can
D. Shall, can’t , may
解析：考查情态动词。Must引导一般疑问句，肯定回答用must，其否定回答为needn’t，can在这里表示许可的意思，may表示可能性，句意：我必须马上清扫教室吗？不，你比比清扫，你可以放学之后清扫。故选A