People have planted a lot of trees and grass in order to ____ wind and sand in the desert.

A．hold down       B．hold up        C．hold back      D．hold out

People have planted a lot of trees and grass in order to ____ wind and sand in the desert．

A．hold down     B．hold up             C．hold back           D．hold out

People have planted a lot of trees and grass in order to ____ wind and sand in the desert．

1. A.
   hold down
2. B.
   hold up
3. C.
   hold back
4. D.
   hold out

．People have planted a lot of trees and grass in order to ____ wind and sand in the desert．

A．hold down     B．hold up             C．hold back           D．hold out

．People have planted a lot of trees and grass in order to ____ wind and sand in the desert．

A．hold down     B．hold up             C．hold back           D．hold out