Tom,finish your homework first,or you _____watch TV

问题描述:

Tom,finish your homework first,or you _____watch TV
Ashan't
Bmustn't
Cneedn't
Dmay not
选A,为什么,请详细作答.

选A,以上解释都不对,shan't表示不准,不应当,是shan't而不是shall not,shan't 比mustn't好.