15．(2010·江苏南京期末)In 1948, three American scientists invented ______ transistor, which is ______ small electronic device to control an electric current.

A. the; a　 　　　　　　　　　　　　　 B. a; a

C. the; the　 　　　　　　　　　　　　 D. a; the

[答案]

14．The length of time spent exercising ______ the sport you are training for.

A. calling for　 　　　　　　　　　 B. calls for

C. depending on　 　　　　　　　 D. depends on

13．The physicist has made ______ discovery, which is of ______ great importance to the progress of science and technology.

A. /; /　 　　　　　　　　　　　　　　　 B. a; a

C. a; /　 　　　　　　　　　　　　　　　 D. /; a

12．It was because the water had risen ______ we could not cross the river.

A. that　 　　　　　　　　　　　　　　 B. where

C. which　 　　　　　　　　　　　　　 D. when

11．T　　 hey supplied me goo

d living ______， so I had ______ happy experience.

A. conditions; a　 　　　　　　　　 B. condition; a

C. conditions; /　 　　　　　　　　 D. condition; /

10．The conference had been held to discuss the effects of tourism ______ the wildlife in the area.

A. in　 B. on

C. at　 D. with

9．-Will you go skiing with me this winter vacation?

-It ______.

A. all depend　 　　　　　　　　　　 B. all depends

C. is all depended　 　　　　　　 D. is all depending

8．Every minute should be made full ______ of ______ for the coming examination.

A. use; preparing　 　　　　　　　　　　 B. use; to prepare

C. using; preparing　 　　　　　 D. using; to prepare

7．-I wish Bill would drive us to the station.

-He has ______ to take us all.

A. a too small car　 　　　　　　 B. too small a car

C. very small a car　 　　　　　　 D. such small a car

6．Her son’s excellent work ______ his rise in the company, while her daughter’s laziness ______ her failure in the entrance exams.

A. led in; resulted from

B. led to; resulted in

C. led in; resulted to

D. led for; resulted from