21、The sun heats the earth , __ _　makes it possible for plants to grow .

A. where

B. when

C. that

D. which

答案：D。

22、There is a ________ of two hours with the 7:40 train.

A. delay

B. change

C. schedule

D. timetable

答案：A。

23、You can make a lot of friends if you_ ____ this club .

A. take part in

B. join

C. enter

D. come in

答案：B。

24、You should ______ with your name, sex, age and address.

A. fill in the form

B. filling the form

C. full of the form

D. full the form

答案：A。

25、I _______get up late, but now I usually get up at six in the morning.

A. used to

B. am used to doing

C. am used to

D. get used to doing

答案：A。