Scientists will have to ________ new methods of increasing the world's food supply.

1. A.
   come up
2. B.
   come up with
3. C.
   come over
4. D.
   come across

A. come up 　　　　  B. come up with    C. come over  　　 D. come across

Scientists will have to ________ new methods of increasing the world's food supply.

[　　]

Scientists will have to ________ new methods of increasing the world's food supply.

[　　]

Scientists will have to come_______ new methods of increasing the world’s food supply.

  A. up for         B. up with          C. out             D. on