The world’s population is getting larger and larger, so scientists are trying to _______ new ways to solve the food problem.
A.catch up with | B.keep up with | C.come up with | D.make up with |
The world’s population is getting larger and larger, so scientists are trying to _______ new ways to solve the food problem.
A.catch up with | B.keep up with | C.come up with | D.make up with |