I should not have laughed if I you were serious. (2013·江苏，30)
A. thought
B. would think
C. had thought
D. have thought
网友回答
A. thought
B. would think
C. had thought
D. have thought
解析：C
解析 考查虚拟语气。句意为：如果我当时想到你是认真的，我就不会笑了。由句意知，此句是与过去事实相反的虚拟语气，故从句结构为had done。