---Dad,mustwewaituntilthelightbecomesgreen?       ---Y...

问题详情：

 ---Dad, must we wait until the light becomes green?

        ---Yes, I’m afraid we ______. That’s the traffic rule.

        A. can            B. may              C. have to         D. need

【回答】

C    

知识点：情态动词

题型：选择题