.--I sent him a most interesting story book by mail this morning.
--You so; he's ing tomorrow morning.
A. needn't do
B. needn't have done
C. don't need to do
D. didn't need do
网友回答
A. needn't do
(答案→)B. needn't have done
C. don't need to do
D. didn't need do
解析：句意：--今天早上我用邮件给他发了一个非常有趣的书。--你不必这么做，明天早上他就来了。Needn’t have done“过去本没有必要做，而做了”，是虚拟语气，A. needn't do和 didn't need do都是过去没有必要做， C.don't need to do 现在没有必要做，所以选B。