Question

But for their help, we ______ the program in time.

A. can not finish
B. will not finish
C. had not finished
D. could not have finished

Answer 1

答案D
考查虚拟语气。根据But for their help要不是他们的帮助；可知这是一个与过去事实相反的含蓄的虚拟语气句，后面主句应该使用情态动词+have done;句意：要不是他们的帮助，我们不能够及时完成这项计划。