20. ______ from other continents for millions of years, Australia has many plants and animals that cannot be found anywhere else in the world.

　　　 A. Being separated　　　　　　　　　　　　　　　　　　 B. Having separated

　　　 C. Having been separated 　　　　　　　　　　　　 D. Separating

19. A modern city has been set up in _______ was a wasteland ten years ago.

　　　 A. what　　　　　　　　　　 B. which　　　　　　　　　 C. that　　　　　　　　　　　 D. where

18. There was a loud scream from the backstage immediately after the concert ended, ________?

　　　 A. wasn’t there　　　　　 B. was there　　　　　　　 C. didn’t it　　　　　　　　 D. did it

17. I had to buy ______of these books because I didn’t know which one was the best.

　　　 A. both　　　　　　　　　　 B. none　　　　　　　　　　 C. neither　　　　　　　　　 D. whole

16. _______ you call me to say you are not coming, I’ll see you at the theatre.

　　　 A. If　　　　　　　　　　　　 B. Whether　　　　　　　 C. Until　　　　　　　　　　 D. Unless

15. He speaks English well indeed, but of course not _______ a native speaker.

　　　 A. as fluent as　　　　　 B. more fluent than　　 C. so fluently as　　　　 D. much fluently than

14. He got well-prepared for the job interview, for he couldn’t risk________ the good opportunity.

　　　 A. to lose　 　　　　　　　 B. losing　　　　　　　　　 C. to be lost　　　　　　　 D. being lost

13. He transplanted the little tree to the garden _______ it was the best time for it.

　　　 A. where　　　　　　　　　 B. when　　　　　　　　　　 C. until　　　　　　　　　　 D. that