—MayIwatchTVforawhile,Mum? —Yes,butyou       finishyour...

问题详情：

—May I watch TV for a while, Mum?

  —Yes, but you        finish your homework first.

  A. may                            B. must                        C. need                        D. can

【回答】

B

知识点：情态动词

题型：选择题