-Let's go to the concert tonight, Mary.
-Sorry, I ____. I have to help my mom with the housework.
- A.needn't
- B.can't
- C.mustn't
- D.shouldn't
正确答案及解析
正确答案
B
解析
句意:——玛丽,今晚我们去听音乐会吧。——抱歉.我不能去。我不得不帮妈妈做家务。needn't没必要;can't不能;mustn't禁止;shouldn't不应该。结合句意可知,B正确。