题目内容：

_1.___There were few people on the earth, and natural resources seemed to be unlimited. Today things are different. The world has become too crowded. We are using up our resources too quickly, and at the same time we are polluting our environment with dangerous chemicals _2.__.

Everyone realizes today if too many fish are taken from the sea, there will soon be none left. Yet, with modern fishing methods, more and more fish are caught. We know that if too many trees are cut down, forests will disappear and nothing will grow in the land. Yet , we continue to use bigger and more powerful machines to cut down more and more trees. __3.__ However, in most countries waste products are still put into rivers or into the sea, and there are few laws to stop this. We know, too , that if the population of the world continues to rise, in a few years, there will not be enough food.

_4._ If we eat more vegetables and less meat, there will be more food available for everyone. Land that is used to grow crops feeds five times more people than land where animals are kept. __5._ the world population will not rise so quickly if people use modern methods of birth control. Finally, if we educate people to think about the problems, we shall have a better and cleaner planet in the future.

A. What can we do to solve these problems?

B. So we should try our best to protect the environment.

C. In the past, man didn’t have to think about the protection of his environment.

D. We realize that if the rivers are polluted with waste products from factories, we will die.

E. Why do some people do so foolish things?

F. If we continue to do this, human life won’t survive in the future.

G. Out natural resources will last longer if we learn to recycle them.