问题

The scientists are beating their brains, trying to ______ a solution to the problem.

A:look up to
B:live up to
C:come up with
D:keep up with

正确答案是：

同类题型

They ________ out the problem, but failed. –What a shame ! I never thought it was going to happen like that.

Do you plan yourhomework at home—Yes, of course.

Most students expect ____more review classes before the exams

The resealcohol.

ring Festival, a traditional Chinesefestival, is celebrated in