We the difficulty together but why didn't you tell me?A. should faceB. might faceC. could

问题补充：

We the difficulty together，but why didn you tell me?

A. should face

B. might face

C. could have faced

D. must have faced

答案：

A. should face

B. might face

(答案→)C. could have faced

D. must have faced

解析：考查情态动词。句意：我们本可以共同面对困难，但是你为什么不告诉我呢？后半句用的是一般过去时，由此可知前半句是对过去情况的一种虚拟，所以用“情态动词＋have done”形式。could have done表示过去本可以做某事，而实际上却没有做，符合句意。