The problem is so plex that I'm afraid it will take me several hours to ．
A. put out
B. set out
C. break out
D. figure out
网友回答
A. put out
B. set out
C. break out
(答案→)D. figure out
解析：D 考查短语辨析。put out熄灭，生产；set out出发，着手；break out爆发，突然发生；figure out算出，解决。句意：这个问题如此难，因此我认为我不得不需要花费几个小时来解决它。