21. My father returned at 10 o’clock _____ of June 15. (2000重庆)

　　　　　　　 A. in the night B. by the night C. on the night D. at night

20. They got _____ the foot of the mountain just now.

　　　　　　　 A. at B. in C. to D. off

19. What’s the difference _____ a sheep and a goat?

　　　　　　　 A. from B. to C. between D. among

18. It will stop the sand _____ moving _____ the rich farmland in

　　　　　　　 the south.

　　　　　　　 A. from; toward B. from; to C. into; towards D. at; down

17. We visited him _____ his workplace _____ the young trees.

　　　　　　　 A. in; beside B. at; along C. at; among D. to; between

16. English is spoken ____ a first language _____ most people in

　　　　　　　 the USA.

　　　　　　　 A. by; as B. as; by C. for; of D. like; in

15. Many old things _____ show were used _____ keeping tea hot.

　　　　　　　 A. at; to B. on; for C. for; on D. in; as

14. _____ a few years’ time, it will be covered _____ many

　　　　　　　 thousands of trees.

　　　　　　　 A. In; with B. After; by C. In; on D. After; over

13. Is the girl _____ red _____ duty today?

　　　　　　　 A. with; on B. on; for C. of; at D. in; on

12. ____ Christmas Eve, children all over Britain put a stocking

　　　　　　　 _____ the en of their beds before they go to sleep.

　　　　　　　 A. At; by B. During; in C. On; at D. In; before