53. He was about halfway through his meal　　　　　 a familiar voice came to his ears. ( 06辽宁 )

A. why 　　　　　　　　 B. where　　　　　　　 C. when　 　　　　　　　　　 D. while

52. _________ environmental damage is done, it takes many years for the ecosystem (生态系统) to recover. ( 06江苏 )

A. Even if　　　　　 B. If only　　　　 C. While　　　　　　 D. Once

51. I had just stepped out of the bathroom and was busily drying myself with a towel ____ I heard the steps.　 ( 06湖南 )

A. while　　　　　　　　 B. when　　　　 C. since　　　　　　 D. after

50. "You can't have this football back 　　　　　you promise not to kick it at my cat again," the old man said firmly.　 (06广东)　

A. because　　　　 B. since　　　　　 C. when　　　　　 D. until

49. Jenny was very sad over the loss of the photos she had shot at Canada, 　　　　　　this was a memory she especially treasured.　 (06广东)

　 A. as　　　　　　　 B. if　　　　　　 C. when　　　　　 D. where

48. --- How long do you think it will be _________ China sends a manned spaceship to the moon?

　 --- Perhaps two or three years.　 (06福建)

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

47. 　　　you’ve tried it. you can’t imagine how pleasant it is. (06北京)

A. Unless　　　　　　　　　　 B. Because　　　　　　 C. Although　　　　　 D. When

46. The more I think about him, the more reasons I find for loving him ___ I did. ( 05 湖南 )

　 A. as much as　 　　　 B. as long as　 　　　 C. as soon as 　　　　 D. as far as

45. Allow children the space to voice their opinions, __________ they are different from your own. ( 05 湖南 )　　　 　

　A. until　　　　　　　 B. even if　　　　　　　　　　 C. unless 　　　　　　　 D. as though　 　　

44. -Did Jack come back early last night?

　　　 -Yes. It was not yet eight o’clock 　　　　　he arrived home. ( 05 福建 )

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