用can.can't,must,mustn't,will,have,to填空
用can.can't,must,mustn't,will,have,to填空
用should,shouldn’t,must,mustn’t,needn’t,can’t ,may,have to 填空
用can,must,can't,mustn't填空
用can/can't;must/mustn't填空
用must,mustn't,can,can't填空
用can,may,must,can't,mustn't填空.
用can,may,must,can't,mustn't 填空
can,can't,must,mustn't,needn't,be allowed to,have to,don't h
用can,can't,must或have to 填空
几个选词填空,must 、can、mustn't、can't
用could,can,can't,must,mustn't need't may填空
用can,must,musn't,have to,has to填空