Environment Pollution must be curbed for the benefit of people. I have traveled through half of China from south to north， I found that I can not see a clear river or lake. When I looked up in the sky， I found its color was not blue at all， it is gray！ We have lost the beautiful globe for ever， I thought. So I think we have to take some measures to fight pollution.
四、比较与对比法(Development by Comparison and Contrast)
常用到的过渡词有两类：
1. Likeness： like， likewise， similarly， in the same way， too， also， correspondingly， equally， as
2. Difference： however， but， yet， nevertheless， on the contrary， in contrast， whereas， on the one hand...on the other hand， instead， still， rather， although， though， even though
范文：
Good manners are important in all countries， but ways of expressing good manners are different from country to country. Americans eat with knives and forks； Japanese eat with chopsticks. Americans say “Hi” when they meet； Japanese bow. Many Americans open doors for women； Japanese men do not. On the surface， it appears that good manners in America are not good manners in Japan， and in a way this is true. But in any country， the only manners that are important are those involving one person"s behavior toward another person. In all countries， it is good manners to behave considerably toward others and bad manners not to. It is only the way of behaving politely that differs from country to country.
运用这种展开手段时，作者经常会忽略以下几个问题：对比不当，对比不全面。
五、分类法（Development by Division and Classification）
常用到的词汇有：divide into， classify ， group， there are ... kinds/ sorts/ types/ groups/ ect.
范文：
There are medium friends， and pretty good friends， and very good friends indeed， and these friendships are defined by their level of intimacy....We might tell a medium friend， for example， that yesterday we had a fight with our husband. And we might tell a pretty good friend that this fight with our husband made us so mad that we slept on the couch. And we might tell a very good friend that the reason we got so mad in that fight that we slept on the couch had something to do with that girl who works in his office. But it"s only to our very best friends that we"re willing to tell all， to tell what"s going on with that girl in his office.
Judith Viorst， “Friends， Good friends”
在使用分类法的时候，最重要的是确定正确的分类标准，切忌以不同的标准进行分类。
病例分析：
There are many kinds of books such as literature books， science books， children books， story books， paperback books， etc. They all can bring us happiness， joy and sometimes sorrow. They can also make us wise. Books are people"s friends.
六、因果法（Development by Cause and Effect）
常用到的过渡词有：therefore， consequently， accordingly， as a result， hence， so that， thus/ since， because， for， due to， for this reason， owing to.
范文：
Why are there changes in people"s diet？ There are two major reasons， I think. First， nowadays people can afford to buy much more expensive food with better nutrition. Second， people now pay more attention to the quality of it， because they know it is of great benefit to their health to diet in a scientific way. Therefore they try their best to improve the structure of their food.
使用这个展开方法最重要的当然是不要将没有因果关系的两个事物牵强附会在一起。
病例分析：
Children are becoming cleverer and cleverer because of television. I often find the neighbor children say some adult words which are often heard from TV. I once heard a boy of five say to a girl of about four that it was not easy for me to say that I love you. Children are really growing faster than ever before.
In recent years the crime rate is getting higher and higher， and the reason， according to me， is that man is getting meaner and meaner. Some people say that man is not as honest as before， and I think that is right. If they are not honest， they will do something wrong， and that would cause the crime rate rise to a high level.
七、定义法（Development by Definition）
范文：
Falling in love is an experience that almost everyone has at least once and usually several times. To fall into love is to fall into a profound set of emotional experiences. There may be a range of physical symptoms such as dry mouth， pounding heart， flushed face， and knotted stomach. The mind may race， and fantasy， especially about the loved one， is rampant. Motivation to work， play， indeed for anything except the lover， may fall to zero. As the love feelings develop， strange feelings of passion may occur. In fact， passionate love is essentially the same as romantic love， except that the focus is more specifical on the emotional intensity and sexual passion.
八、过程法(Development by Process)
范文：
To make wine， begin with grapes that have not been washed. (This is important because the skin contains a natural yeast which will aid in the fermentation process.) In a crock crush the grapes by hand so that the skins crack and the juice runs out. Leave the grapes at room temperature (or slightly warmer) to begin fermenting. Cover the crock， to keep fruit flies from getting into the wine. In a day or two the pulp should be at the top and the juice at the bottom. Stir， so that pulp and juice are mixed. At the end of five days， press the mass so that the liquid remains， and the solids are removed. If you have no winepress， you can squeeze the mass through cheesecloth (a material full of fine holes， like a screen)， wringing the juice out of the cloth by hand. At this point， if you want sweet wine adds one or two pounds of sugar per gallon of wine， and let it dissolve in the juice.
病例分析：
To get the most out of his textbooks， a student should follow several steps very carefully. He should make a survey of each book to get a general idea of what the book contains. He should read for understanding and formulate questions. He should make notes of the major points of each chapter. He should test himself to be sure that he can answer questions likely to be raised in class and in examinations. He should review his notes and reread any parts of the book that are unclear to him.
比较：