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：考察虚拟语气。根据but后面的过去时可知是与过去事实相反，那么主句中应该使用情态动词+have done的形式。故排除AB。D项只表示对过去情况的肯定推测，不表示虚拟，故C正确。