【题目】But for their help, we ________ the program in time.
A. can not finished B. will not finish
C. had not finished D. could not have finished
在线课程【答案】D
【解析】
考查虚拟语气。But for“要不是......”，相当于if虚拟条件句，与过去事实相反，主句用would/should/could have done。句意“要不是他们的帮助，我们不可能及时完成计划。”故选D。