He desperately in vain for something to say to break the silence.
A. thought about
B. cast about
C. talked about
D. set about
网友回答
A. thought about
(答案→)B. cast about
C. talked about
D. set about
解析：选项A“想到”； 选项B“想法设法”； 选项C“谈论”； 选项D“着手，开始做”。 cast about for sth“试图找到某物” 。句意：他拼命地想找到某些话题来打破沉默。