一些内容参考了:)~~
Once man did not have to think about the protection of his environment. 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 natural resources,and polluting our environment with dangerous chemicals. If we continue to do this, human life on earth will not survive.
We realize that 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. Yet, we continue to use powerful machines to cut down more and more trees. We see that if rivers are polluted with waste products, we will die. Yet, waste products are
still put into rivers.
