request作“要求”讲时，后面可以跟宾语从句，从句用虚拟语气，即其谓语部分用“should＋动词原形”，其中should可省略。与此用法相同的还有： 一坚持(insist) 二命令(order，command) 三建议(advise，suggest，propose) 四要求(demand，require，request，desire)

This is his only request that the room __________ after being used. A．be cleaned B．would be cleaned C．is cleaned D．will be cleaned 答案A should be cleaned should被省略。