51. B
52. D
53. B
54. C
55. A
56. I wish I could remember the answers to these questions
57. Because the weather was so bad, we didn't go out
58. This hospital was built 20 years ago
59. Unless he works harder, he'll lose his job
60. Mary suggested going out for dinner
61. My father is the tallest in my family
62. It was such a heavy box that my son couldn't carry it
63. The planet which is the closest to the Eath is Venus
64. We haven't decorated this house for 2 years
65. If he weren't lazy, he wouldn't get bad marks