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 will have a meeting _______ the morning _______ September 8th.[ ]
As we know, England is ______ European country and Singapore is ______Asian country.
Could you please tell _______________________?—Sure. Though I am a little nervous, I would love to.
_______ ham do you have?— _______. I’m afraid we have ______ beef in the fridge.