【正确答案】
Environmental pollution has become one of the greatest problems in the world today. There may be different causes for pollution. First of all, there are so many vehicles in cities, especially big cities. These vehicles give off waste, sometimes even poisonous gases. Second, many factories, such as paper-making mills, let their dirty water directly flow into our rivers and lakes. Third, farmers use more and more chemicals and pesticides. So, our fields are seriously polluted.
These pollutants are harmful to our health. Some rivers have become undrinkable. Some polluted food or vegetables can cause cancer and other diseases. And if we breathe dirty air into lungs, we may fall ill.
Now, some governments are taking measures to solve the problem. For example, our government is making a policy to punish the factories which have made the Huaihe River very dirty. Also, our government is reducing the number of cars in Beijing. I think all of these measures are very necessary. If we all work hard, this problem can be solved in the near future.

【答案解析】[解析] 作文题目清楚地表明文章的中心思想是防治环境污染。通过对提纲要点的分析可以看出，文章各段落的主要内容为：产生污染的原因；污染的危害；防治污染的措施。另外，依据提纲要求，段落的展开可以采用列举法。