问题补充:
—You didn wait for Mr. Smith last night, did you?
—Yes, but we . He didn return home at all.
A. don have to
B. needn have
C. didn need to
D. should have
答案:
A. don have to
(答案→)B. needn have
C. didn 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。