How the president____ this effective solution to the problem remains unknown.
A、 put up with
B、 came up with
C、 caught up with
D、 kept up with
【正确答案】：B
【题目解析】：考查短语词义。选项A. put up with(容忍,忍受);选项B. came up with(想出,提出);选项C. caught up with(赶上,追上);选项D. kept up with(紧跟,跟上)。所以根据句意,选B【参考译文】总统如何想出解决这个问题的有效办法还不得而知。
