问题
选择题
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
答案
答案：D
本题考察虚拟语气.But for起到了对过去虚拟的条件句作用,后面自然要选would/could/might/should+have done结构了.