阅读下面的短文，然后按照要求写一篇150词左右的英语短文。 【阅读材料】 A Thirsty World Three-fourths of the earth’s surface is covered by water, some of which is frozen and most of which is salty. In fact, less than one percent left for all the living things. Now fresh water is becoming scare, but more and more is needed because of the increasing number of people. Some industries also use amounts of fresh water in the production of things such as steel, paper, and rubber. These factories have polluted water flow into rivers without making it clean. What’s more, people in the city have much dirtied water piped into ditches after cooking every day. Scientists estimate that the need for fresh water will have doubled by the year 2003. This means that we must find new ways of saving it or producing it. Some nations have worked on the problem and are already sharing their information with others. They are trying to keep their rivers from being polluted. Deep wells are also being dug, and rainwater is being collected in huge artificial lakes. In one way or another, they hope to provide enough water to satisfy the needs of their people. For example, one important wayof producing water is to distill(用蒸馏法提取) it from sea water. After the salt has been removed, sea water can be used not only for drinking but also for industry and irrigation. However, the equipment for distillation process is very expensive. Distilled water might be as dear as gold if pollution goes on. [写作内容] 1.      概括短文的内容要点，该部分的字数大约30； 2.      就”环境污染的原因与控制”这个主题发表你的看法，至少包括以下的内容要点，该部分的字数大约120； a)      环境污染是由什么原因引起的？简单地举例子说明。 b)     为了解决污染问题，国家政府部门应该做些什么？ c)      为了解决污染问题，公民做些什么？ d)     为了解决污染问题，我们学生应该做些什么？ 【写作要求】 可以利用实例或其他论述方法支持你的论点，也可以参照阅读材料的内容，但不得直接引用阅读材料中的句子。