41. The reason _____ I can‘t come is that I have to prepare for the coming exam.

　　A. for B. as

　　C. because D. why

　　答案：D

　　42. She studied hard at school when she was young; _____ contributes to her success in her career.

　　A. that B. so that

　　C. so D. which

　　答案：D

　　43. Sound waves travel in the air in much the same way _____ water waves spread on the water.

　　A. as B. that

　　C. where D. in which

　　答案：A

　　44. I‘ve got a bottle of beer， but I haven’t got anything _____ I can open it with.

　　A. that B. what

　　C. where D. which

　　答案：D

　　45. Writers can accurately describe objects ______ have never seen.

　　A. who B. if they C. they D. that

　　答案：C

　　46. It wasn‘t such a good present _____ he had promised me.

　　A. that B. as

　　C. which D. what

　　答案：B

　　47. Perhaps the day will come _____ people will be able to breathe clean air in cities.

　　A. when B. while

　　C. as D. since

　　答案：A

　　48. To make up an objective test， the teacher writes a series of questions， _____ has only one correct answer.

　　A. each of which B. some of which

　　C. which D. what

　　答案：A

　　49. A higher crime rate exists in cities _____ a large percentage of unemployment.

　　A. where have B. that have

　　C. which they have D. that having

　　答案：B

　　50. Scientists call Newton‘s idea _____ gravitation reaches throughout the universe the law of universal gravitation.

　　A. when B. which

　　C. that D. where

　　答案：C