52. It is one’s duty to do sth.做某事是某人的责任
51. burst in打断;闯入/ burst into the room闯入房间/ burst out突然开始
49. tear sth. in two把某物撕成两半 50. chase sb. away/off 把某人赶走
47. must have forgotten to do sth. 一定已忘记做某事 48. fall down倒下;(计划等)失败
46. in reference to/in regard to/regarding 关于...
44. remind sb. of sth. 提醒某人有关某事 45. nice and非常
42. take on雇用;承担;呈现 43. be popular with 受到...的欢迎
40. a famous cross-talk master一位著名的相声大师 41. in request需要,受欢迎
38. on sale出售/for sale待售 39. be worthwhile值得
37. win first place in the competition在比赛中获第一名