55. ...had been working...
56. had already left
57. had been living
58. had ate
59. had been writing
60. had forgotten
61. had passed
62. had been studying
63 - b
64 - a
65 - a
66 - c
67 - a
68 - b
69 - c
70 - a
71 - b
72 - a
73 - a
74 - a
75 - a
76 - a
77 - b
78 - c
79 - c
80 - b