----You didn’t wait for Mr. Smith last night did you?---Yes but we. He didn’t return

问题补充：

----You didn’t wait for Mr. Smith last night, did you?

-----Yes, but we. He didn’t return home at all.

A. don’t have to

B. didn’t need to

C. needn’t have

D. should have

答案：

A. don’t have to

B. didn’t need to

(答案→)C. needn’t have

D. should have

解析：考查情态动词用法。句意:昨天晚上你没有等Mr Smith，是吗？—不，我等他了。可数我们本不需要这样做。他昨天晚上根本没有回来。Needn’t have done本不需要做某事，实际上却做了；should have done本应该做某事，实际上却没有做；本题Mr Smith没有回来，我们本不必等他的。故C正确。