We the difficulty together，but why didn't you tell me?
A. should face
B. might face
C. could have faced
D. must have faced
网友回答
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。