51. Helen told me everything _____ she knew about it.

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

50. He is one of the students who, I’m sure, always _________best.

　 A. do their　　　 B. does his　　　　　 C. try my　　　　　 D. do the

49. Every hour and every minute __________ long and tiring while waiting for someone in the hot sun.

　 A. are　　　　　 B. will be　　 C. seems　　　 D. has seemed

48. John, together with his three classmates, _________ punished for having stolen the car.

　 A. was　　 B. \　　　　　 C. were　 　　　　D. who

47. As the school is short of money, the number of the books in this library _________ unchanged for three years.

　 A. was　　　　　 B. remains　　　　　 C. remain　　　　 D. has been remained

46. __________ when he saw the UFO that he couldn’t move a little.

　 A. He was frightened enough　　　　　　　 B. He was too frightened

　 C. So frightened he was　　　　　　　　　 D. So frightened was he

45. I’ve already told you that I ‘m going to buy it, _________________.

　 A. however much it costs　　　　　　　　 B. however does it cost much

　 C. how much does it cost　　　　　　　　 D. no matter how it costs

44. No sooner had we reached the top of the hill ________we all sat down to rest.

　 A. when　　 B. then　　　　　　 C. than　　　　　 D. until

43. I will accept any job ________ I don’t have to get up early.

　 A. lest　　　 B. as long as　　　　　 C. in case　　　　 D. though

42. Scientists say it may be five or ten years ________ it is possible to test this medicine on human patients.

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