Question

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

Answer 1

A

试题分析：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。