----Mary broke up with me!
----You have forgotten about the Valentine's Day．
A. shouldn't
B. couldn't
C. needn't
D. mustn't
网友回答
A. shouldn't
B. couldn't
C. needn't
D. mustn't
解析：考查情态动词+have done的用法：A．shouldn't have done本该做…而没有B．couldn't have done过去不可能做了，C．needn't have done 本不必做…而做了，D．mustn't和完成式连用只能用于肯定句，句意：--玛丽和我分手了！--你本不该忘记情人节。选A。