----Did you make it at last?
----Yes. But for your help, it a serious loss.
A. would cause
B. must have caused
C. might cause
D. would have caused
网友回答
A. would cause
B. must have caused
C. might cause
(答案→)D. would have caused
解析：考查虚拟语气。句意：--你最终成功了吗？--是的。要不是你的帮助，将会造成巨大的损失。but for要不是，根据第一句的did可知，是对过去事情的虚拟，本题的but for短语相当于if it hadn’t been for your help，主句应该使用would have done sth。故选D。