【正确答案】 A

【答案解析】本题考查情态动词。分析结构可知句子的前半句是对事实进行阐述，后半句则应该是对这种事实进行推测，根据mess和clean两词，可知应选A，表示不可能。shouldn't have done sth．表示已做了不应该做的某事：mustn't have done这种形式在英语中不存在；wouldn't have done sth．语气比can't have done委婉，而且是对过去未做的事情进行假设。例：The flowers shouldn't have been watered．这些花不应当浇水(实际上已浇了)；If you had done as what I said，this wouldn't have happened．如果你按照我说的去做，就不会发生这种事了。