Pollution is a serious problem. Scientists have some good ways to save it. A. come up wit

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→)A. come up withB. come onC. come outD. come up解析：句意：污染是个严重的问题，科学家们已经想出了解决的办法。A想出（注意，办法）B继续C出来，出版。D走上前，故选A。

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