I , but I didn't think you were serious.
A. shouldn't laughed
B. wouldn't laugh
C. shouldn’t have laughed
D. needn’t have laughed
网友回答
A. shouldn't laughed
B. wouldn't laugh
(答案→)C. shouldn’t have laughed
D. needn’t have laughed
解析：shouldn't have done意思是:本不应该做却做了.