—How amazing it is that astronauts are exploring outer space!
—It's a challenge, I guess, man against nature.
A. of
B. for
C. by
D. about
网友回答
(答案→)A. of
B. for
C. by
D. about
解析：A 考察介词。应答句中的I guess是插入语，因此所填介词与challenge连用，表所属，使用of。选A。句义：我猜想它是人对自然的挑战。