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

正确答案是：

标签： come , pollution , up

同类题型

What’s the matter with your mother? —She ______ a sore throat.

sheto her grandma’s every week?

The poor girl needs an operation. But it will ________ a lot of money.

Many boy students think math is _____ English.–I agree. I’m weak in English.

_______ is your home from school?一Two kilometers．