问题
选择题
Pollution is a serious problem. Scientists have _____ some good ways to save it.
A．come up with
B．come on
C．come out
D．come up
答案
答案：A
题目分析：句意：污染是个严重问题。科学家们想办法来解决她。A 想出来；B 加油；C 出版；D 走近；结合语境故选A。
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