问题补充:
Whoever leaves the room last must that all the lights are turned off.
A. is sure
B. make sure
C. find out
D. look out
答案:
A. is sure
(答案→)B. make sure
C. find out
D. look out
解析:短语必须。B确定;C发现,查明;D当心;A项不能放在must的后面。句意:任何一个最后离开房间的人必须确定所有的灯都被关闭了。根据句意说明B正确。