问题补充:
—Mum,I watch TV now ?
—No, you finish your homework first.
A. may, need
B. can, have to
C. do, must
D. may , must
答案:
A. may, need
(答案→)B. can, have to
C. do, must
D. may , must
解析:句意: -妈妈,现在我可以看电视吗?-不,你必须先完成你的家庭作业。may 或can 可以表示征求别人的许可;need 需要;have to 必须,不得不;must 必须;根据句意可知选B。