51. I happened ______ that news from a magazine.       A. known                 B. to be known C. to know D. know                   52. Do you understand _______?                                 A. what done             B. what doing C. what to do D. what do 53. Can somebody show me ______ the film in this cinema? A. how to changed B. how change C. how changing D. how to change 54. Don’t forget _____ the letter I gave you. A. to post       B. posting C. post D. posted 55. There was a lot of traffic, but we managed _____ to the airport in time. A. are gone B. going   C. to go D. to be going 56. Jill didn’t afford _____ a car.                                 A. buy                          B. to buy C. buying D. bought 57. They had a boy ______ that yesterday.                 A. done                         B. to do C. did D. do 58. We get our mail ______ yesterday.                     A. been delivered          B. delivered C. delivering D. to deliver  59. We’ve got a new computer in our office. I haven’t learnt how ______ it yet. A. to operate B. operating C. operate D. be operated 60. We were all too afraid to speak. Nobody dared ______ anything. A. saying B. being said C. says D. to say