1a 

2b

3d

4b

5c

6a

7b

8a

9a

10b

11b

12c

13d

14b

15a

16c

17d

18d

19b

20b

21. collecting

22 taking

23 turn

24 will have

25 go

26 since it was raining, we decided..

27 she was busy, so she couldn't join us

28 what about going to the cinema tonight?

29 I suggest using energy-saving bulbs

30 she wasn't beautiful but she took part in a beauty contest

31 if you work hard, you will pass the exam

32 unless you start working now, you won't...

33 we are delighted that you passed....

34 she wanted to go home because she was tired

IV.

1. electricity

2.by

3.energy

4. save

5. machines

6. how much

7.in

8 money