问题
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
B:come on
C:come out
D:come up
正确答案是：
同类题型
We don’t know who ____ for the murder, but the policemen will tell us the truth soon.
He was crossing over to _____ side of the road when I saw him.
Look at that girl! Is it Susan?—No, it _______ be her. She has gone back to her hometown.
How much do I need to _______ you for this book? —Twenty yuan.