7. --- May I go swimming now?

问题描述:

7. --- May I go swimming now?
--- No, you ______. You must finish your homework first.
A. mustn’tB. may notC. couldn’tD. needn’t [1298]
请问这个空填什么呀?答案说是A但是我感觉应该是C吧,你看一下应该选择哪一个呀?谢谢啦.嘿嘿.

是选a
mustn't表示禁止,语气强烈,从后文可以看出你必须先完成作业.