—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
(答案→)A. shouldn't
B. couldn't
C. needn't
D. mustn't
解析：考查情态动词的完成式用法：shouldn’t have done本不该做而做了，couldn’t have done过去不可能做了，needn’t have done本不必做而做了，must如果接完成式要用肯定，句意：--玛丽和我分手了。--你不该忘记情人节。选A。