21. Dogs have a very good of smell and are often used to search for survivors in an earthquake。

　　A. sense B. view C. means D. idea

　　22. The house I grew up has been taken down and replaced by an office building。

　　A. in it B. in what C. in that D. in which

　　23. Tom has already given up the of smoking for the sake of health。

　　A. custom B. habit C. hobby D. convention

　　24. Stephen Bullon is the only man in the village today that has survived the war。

　　A. live B. lived C. alive D. active

　　25. As she entered the room she could see big bright lights hung from the 。

　　A. roof B. top C. ceiling D. height

　　26. Those experiments have laid a solid foundation for his research in material science。

　　A. far B. deep C. farther D. further

　　27. The weather forecast says it is going to clear soon。

　　A. up B. out C. over D. about

　　28. He will come to call on you the moment he his work。

　　A. will finish B. finishes C. finished D. to finish

　　29. such a good chance, how could she let it slip away?

　　A. Having given B. Giving C. Having been given D. Give

　　30.Previous his departure, he addressed a letter to his。

　　A. to B. of C. in D. from

　　答案：A D B C C D A B C A