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

问题补充：

We the difficulty together, but why didn’t you tell me?

A. should face

B. might face

C. must have faced

D. could have faced

答案：

A. should face

B. might face

C. must have faced

(答案→)D. could have faced

解析：考察情态动词用法。根据why didn’t you tell me?中的过去时可知本书是对过去情况进行虚拟，故D正确。Must have done一定做了某事；could have done本可以做，实际上却未做；结合句意可知D正确。我们本可以一起面对困难，但是为什么你不告诉我？