污染，人类的严重威胁

提纲

　　1.污染是科技进步带来的最严重问题。

　　2.污染对人类和地球造成的危害。

　　3.解决污染的办法。

　　Nowadays， we have many conveniences in our life which have been brought about by technology and science. However， the advances in technology and science have caused some very dangerous problems. The most critical problem is pollution —— pollution of the air， land and water.

　　First， air pollution has done a lot of damage to the ozone layer. Without ozone， not only we ourselves but also plants and animals would be exposed to dangerous rays from the sun. Secondly， this air pollution has warmed the atmosphere. Many scientists think that the wanning may some day melt the polar ice caps， thus raising the sea levels. This will mean that many parts of the world would be submerged below sea level. Thirdly， polluted crops and water are directly harmful to our health.

　　Since the problems created by pollution are becoming more and more serious， people need to be educated so that they will stop damaging the earmh —— our home. Furthermore， governments must take action to prevent individuals and companies from harming our environment.