The scientists are beating their brains trying to ________ with a solution to the problem．

1. A.
   end up
2. B.
   come up
3. C.
   catch up
4. D.
   put up

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

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

A．come about        B．come across       C．come out          D．come up with

The scientists are beating their brains trying to ________ a solution to the problem of how to predict earthquakes correctly.

A. come up with 　　　　 B. come into

C. come about 　　　　　 D. come out with