10.　 In my opinion, the best solution to this problem is to carry out the system of praise and punishment firmly.

9.　　 Something must be done to prevent factories from polluting the air.

8.　　 Our government is doing its best to take measures to fight against pollution.

7.　　 We must make good use of water and avoid polluting it.

6.　　 A large quantity of trees should be planted.

5.　　 Laws have been passed to protect our environment.

4.　　 Now more and more people have come to realize how serious this problem is.

3.　　 With the development of agriculture and industry, more and more waste is produced.

2.　　 It is very important to deal with the rubbish in cities. Rubbish should be treated properly.

1.　　 As we know, pollution does great harm to human beings.