We last night, but we went to the party instead.
A. must have studied
B. might study
C. should have studied
D. would study
网友回答
A. must have studied
B. might study
(答案→)C. should have studied
D. would study
解析：考查should have done本该做…而没做，句意：我们昨晚本该学习的，但去参加聚会了。Must have done过去一定做了。选C。