A-A+
It's rather cold in the room. They______ have
问题详情
It"s rather cold in the room. They______ have turned off the steam a few hours ago.
A．should
B．must
C．ought to
D．could
参考答案
正确答案：B
解析：句意：屋子里相当冷，他们一定在几小时前关闭了暖气。考查must have done结构。这种结构表示对过去事情肯定性很强的推断。意思是“肯定，一定”。
