Somehow, the old man had a dangerous secret, one which could not be discussed in a room on a military base.
A. put out
B. let out
C. set out
D. cut out
网友回答
A. put out
(答案→)B. let out
C. set out
D. cut out
解析：B 考察动词短语辨析。Put out熄灭，出版；let out泄露，放出；set out出发，开始；cut out窃取，删除；句义：不知为什么，老人泄露了一个不能再军事基地的房间里讨论的危险秘密。根据句义说明B正确。