本文提供的是英语专四大作文写作必备三原则，希望对同学们有所裨益。
1. 三段论原则
全文多数情况下分三段。首段与末段都是两句至四句之间，也有五句的情况。中间的一段句子个数肯定会多一些。首段与末段的结论结构都是“总+分”，也有 “总+分+总”的情况。首末段极其重要，所以我们一定要多加操练。也有写成四段的情况，注意这时中间可能有两个段落，但首末段的写法不变，突出其特殊的地位。
2. 组词成段原则
列出每段关键词, 每个词代表一个句子, 然后写出该词代表的句子, 最后将句子串成一段。这样可以尽快使你的思维点连贯起来, 快速成段。
以1992年考题“For a better understanding between parents and child”为例, 介绍一下这种写作方法:
第一步, 我们要仔细阅读“outline”, 然后在写第一段(present situation)的时候会联想到下列关键词汇:误会, 误解—— misunderstanding; 理解——understanding; 抱怨——complain; (父母)过时了—— old?fashioned 或者 behind the times; (向老师或同学)寻求帮助——seek help from...
第二步, 通过这些词汇我们可以造出句子:
misunderstanding—Nowadays there is often a misunderstanding between parents and children.understand—Parents find it difficult to control or even understand their children.complain, old?fashioned—Child complain that their parents are too“old?fashioned”to agree withwhat their children say and do.behind the times—Many children often say that his or her parents are just hopelessly behind thetimes.seek help from—The children will seek help from their friends or teachers instead of from theirparents.
第三步，根据以上句子，我们在句与句之间加入合适的关联词，就可以组成段落了:
Nowadays there is often a misunderstanding between parents and children.On the one hand,parents findit difficult to control or even understand their children.On the other hand, Childrencomplain that their parentsare too“old?fashioned”to agree with what their children say and do.Sowhenever children are in trouble,they will seek help from their friends or teachers instead of fromtheir parents.
3. 句型多样化原则
每段构造1—2个长句。使得文章长短句搭配合理, 行文流畅。这就要求考生在备考时适当地背诵仿写一些长句, 这样大家写作中的句型就可以丰富起来，效果也就会好得多。
请大家仔细揣摩下列段落中精彩的长句, 并进行仿写:
1) There are many ways to keep fit.Firstly, enough exercises is necessary.People can play basketball or table tennis if they have enough time at their disposal.Secondly, proper eating habitsare indispensable。That is to say, never eat too full at lunch while ignoring breakfast, and never takein too much sugar or fat while overlooking vegetables and fruits.Thirdly, high spirits arehelpful.Laughter and humor always makepeople healthy, but anger and anxiety often result inillness.Besides, it is advisable for people to have their physical checkup regularly and to give up badhabits such as smoking and drinking.
2) To bridge this generation gap between parents and children, both of them should be cooperative.For children, they should be considerate of parents for the sake of their hard work.As forparents, theyshould be tolerant toward children.If both of them can take the first step by actuallytalking to one another,it wont be long before the arrival of a better understanding betweenparents and children.
3) As for me, I prefer to live in the city.First, I can enjoy the conveniences offered by ourcivilization.Senond,compared with the undeveloped factors of the country, a city is an ideal placefor me to make a contribution.Of course, I like to take my vacations in the country, relaxing andappreciating the quiet and peacefulnatural beauty.
4) As can be seen from the pictures, smoking is every bit a very harmful habit.Physically, it causes threemillion deaths in the world every year.Financially, it results in a yearly loss of 200 millionU.S.dollars eitherspent on cigarettes or lost in fire accidents caused by smoking.Yet, despite allthese facts, there are stilla lot of people who are still addicted to smoking.According to officialreports, among the 5.8 billion peopleof the world, 1.1 billion are smokers, which take up 20% ofthe total world population.
5) There are three reasons for this effect.Firstly, with the rapid growth of human population, much spacehas been either occupied or destroyed in the process of industrialization and urbanization.Asa result,the space for wildlife to survive is becoming less and less.Secondly, the seious ecologicalproblem,including deforestation, overgrazing and all kinds of pollution, has also done great harm towildlife.Finally,a lot of wildlife species are killed for food, for money, or even for fun, which alsoquickens the extinction of some rare wildlife.
6) Nowadays promise making has become a fashion in every field.But as is shown in the cartoon,some of the promises turn out to be false and deceptive.Just like the most common eggs laid bythe hen, whatenterprises pledge to fulfill is virtually what they should do.
7) As for the crisis, we should take active and effective measures as quickly as possible.Above all,inorder to keep the balance of ecology in the sea, forbidding commercial fishers to go fishing incertain periods of time and areas.Aside from that, all laws and regulations against pollution shouldbe forcefully implemented.Unless we try our best to restore the balance of ecology, there will be noresources availablefor us to survive.
8) Chinese culture is gaining worldwide acceptance.For one thing, Chinese culture, long in history,varied in form and rich in content, has remained one of the most original, ingenious and vitaltraditions among all civilizations.For another, Chinas success in development lays solid basis for theintroduction of its national culture to other countries.