A: I go to the airport to see Uncle David off tomorrow morning mum?B: No you needn’t. Y

问题补充：

A: I go to the airport to see Uncle David off tomorrow morning, mum?

B: No, you needn’t. You may join us if you want to.

A. Must

B. Need

C. Should

D. May

答案：

(答案→)A. Must

B. Need

C. Should

D. May

解析：句意：——妈妈,我明天早上一定要去机场送戴维叔叔吗?——不，你不必。如果你想要去你可以加入我们。must回答的否定用needn ，意思为不必要的，故选择A。