雅思写作：议论文写作黄金法则
I 讨论类
何为讨论类文章，即对一个给定的观点以及与其相对立的观点进行讨论，或就一个话题的两个对立的方面：积极和消极方面进行探讨，发表自己的观点。顾名思义，讨论类文章分为观点类讨论和优缺点讨论。这两种议论类型所对应的问题模式常见的有：Do you agree or disagree, What is your opinion? To what extent do you agree or disagree?等。请看下面的列表来熟悉此类问题模式。
1).Nowadays, some universities offer students skills that assist them to find employment, but some people believe that the main function of a university should be to provide students with access to knowledge for its sake. What is your opinion?
2). Some people think that using animals for experimentation purpose is necessary for the development of science. Do you agree or disagree with this opinion?
3). The main purpose of public libraries is to provide books and they should not waste their limited resources and space on providing expensive hi-tech media such as computer software, videos and DVDs. To what extent do you agree or disagree?
4). Tourism is becoming a good source of revenue for many countries. Discuss both the advantages and disadvantages of exploring this resource.
5). In many countries, the number of elderly people is increasing fast. Does this trend have more positive or negative effects on the society?
以上五题中有对一个观点发表自己观点的，也有给出两个观点再发表自己观点的，也有对一个话题的两个方面进行论述的，这些都属于讨论类，其中1、2、3题属于观点类讨论，而4、5题为优缺点讨论。
2. 结构分析
单边论证
熟悉了问题模式后，我们来分析一下其所对应的文章结构。以上五种问题模式，考生在未接触雅思前较熟悉的是Do you agree or disagree?和 What is your opinion?而通常这两类问题所对应的文章可以用以下的五段论结构来完成：引言段(introduction)提出观点，正文(body)三段通过三个理由来对观点进行论证，结尾段(conclusion)重申一下自己的观点。因为此种结构只对自己支持的观点进行论证，因此叫单边论证，可以用下图来表示：
Introduction
Background+My Opinion
Body:
1.Reason One + Supportiong Sentences(ss表示)
2.Reason Two + SS
3.Reason Three + SS
Conclusion:
Restatement of My Opinion
上述结构中的supporting sentences在议论文中的体现方式是一些论证方法，如举例子(exemplification)，对比对照(contrast& comparison)，列数据(raising figures)，让步(making concession)等来对自己支持的观点进行论证，使考官信服。而此类结构也是中国学生较熟悉的议论文结构，在各类中国的考试中，如高考英语、大学四六级考试等，应用也较广。但是单边论证的缺点，就中国学生而言，是较难扩展论证过程，而且像讲道理、举例子等论证方法必须正确使用，显示其逻辑性才能得到高分。
