What is nature? It's everything that exists in the world independently of people, such as pants and animals, earth and rocks, and the weather. Now more and more people are focusing on the nature. It is no doubt that the nature is important to every human being. No nature, no life. Because of the supplies of the nature, we have lived happily for a long time. And we started to gain every thing available from the nature. And this lasted so long a time. Today, people have discovered that the nature around is getting worse and worse. What is threatening the nature? Air and water pollution, overharvesting of plant and animal species, overpopulation and so on. Overpopulation is the biggest source of pollution. Let's take overpopulation as an example. What does overpopulation feel like? When we move slowly through the city in a tazi. When we enter a crowded slum district. When the temperature is high and when the air is thick with dust and smoke. The streets are crowded with people. The streets seem alive with people. People eating. People washing. People talking ……
正文
