Question

—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

Answer 1

B

试题分析：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。
点评：注意在虚拟语气中，but后面的句子使用陈述语序，要根据前面的虚拟语气的形式来决定后面的时态。