Why is so silent in the room? He asleep in the room.A. should beB. must beC. must have bee

问题补充：

Why is so silent in the room? He asleep in the room.

A. should be

B. must be

C. must have been

D. should have been

答案：

A. should be

(答案→)B. must be

C. must have been

D. should have been

解析：考察情态动词。Should意思是应该，must 一定必须。后面接完成时态，表示对已经完成的的动作进行推断。根据题意，房间没为什么如此安静？他一定是在房间内睡着了。到现在还没醒故选B。