Question

They were abroad during the months when we were carrying out the investigation, or they _____ to our help.

A．would have come

B．could come

C．have come

D．had come

Answer 1

A

解析试题分析：这里when引导的是定语从句，修饰前面的名词months;根据谓语动词were可知事情发生过去，or后是对过去的虚拟，所以应该用would have done，故选A。句意：在我们进行调查期间他们在国外，要不然的话他们就来帮忙。
考点：考查虚拟语气。