I．题目略。
1．make a difference
2．pull down
3．turn off
4．pay for
5．be full of
6．clean up
7．put sth． to good use
8．cut down
9．instead of
10．be good at
11．cut off
12．be good for…
13．upside down
14．be made of/from…
15．throw away
16．听说
17．恢复；使想起；归还
18．建立
19．参加
20．在……中起作用
Ⅱ．题目略。
1．used to
2．turn off
3．pulled down
4．is made from
5．cut down
6．instead of
7．is known for
8．set up
9．put; to good use
10．throw away
Ⅲ．题目略。
1．built; out of rubbish
2．is made from
3．heard of
4．Turn off
5．set up
6．are planted
7．are trying to
8．cut down
9．The number of
10．are good for
11．hotter and hotter
12．play a part in
13．make a difference; lead to
14．instead of
15．for; to use