5.B what
6.B -> have worked
7.C -> buying
8.B -> to
9.A -> is
10.A had taken
11.B competition
12.B pollution
13.A alternative
15.C collector
16.D extinction
17.B spaceman
18.C going
19.A guests
20.D Silver Anniversary
21.B post office
22.C spacecraft
23.C which
24.A that
25.C extinct
26.B non-renewable
27.A fossil fuel
28.C If I hadn't stayed up late last night, I wouldn't have been tired
29.B It was football that he played the whole afternoon
30.A If you had told me the story, I could have helped you
31.B He apologized for having to leave early
