21.——Could I use your English dictionary for a few moments?
—— ________.I’m not using it myself.
A.Come on B.It depends C.Go ahead D.That’s great
22.Read the passage and correct the mistakes, ______..
A.if not B.if any C.if ever D.if never
23.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