—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. needn't have
C. didn't need to
D. should have
网友回答
A. don't have to
(答案→)B. needn't have
C. didn't need to
D. should have
解析：考查虚拟语气。句意：—昨天晚上你没有等斯密斯先生，是吗？—不，我等他了。但是我们本没有必要等他的。他根本没有回来。Need not have done sth本不需要做某事，实际上却做了。故B正确。