This is the earth. The green part is land. The blue part is sea. The white part is clouds. Our earth is very beautiful and interesting. There are rivers, streams, seas and lakes. There are hills and mountains. There are woods, jungles and forests. There are many countries and cities. There are many people live in them. Do you think the earth is very wonderful? 　 　Many years ago, the earth is very clean. But nowadays there is much pollution on the earth. There is air pollution, land pollution and water pollution。People are cutting down the forests. 　 　Many wild animals, birds and insects lose their homes. People are killing animals for their food and their skins. It’s very cruel. People are polluting the land, the water and the air. People must stop doing this. We must save the earth.