问题补充：
But for their help, we the program in time.
A. can not finish
B. will not finish
C. had not finish
D. could not have finished
答案：
A. can not finish
B. will not finish
C. had not finish
(答案→)D. could not have finished
解析：
考查虚拟语气，but for是“要不是”，相当于：if it had not been for their help,实际情况是他们帮忙了，他们不能及时完成计划也是于事实不符合的。
