But for her help we the task in timeA. will not finishB. had not finished C. can not fini

问题补充：

But for her help，we the task in time．

A. will not finish

B. had not finished

C. can not finish

D. could not have finished

答案：

A. will not finish

B. had not finished

C. can not finish

(答案→)D. could not have finished

解析：考查虚拟语气。句意：要不是她的帮助，我们不可能及时完成这项任务。“couldn’t+have+done”表示对过去事情的假设，意思是本来不能够做某事而做了。故选D。