说明文与议论文写作讲座(Exposition &Argumentation)
外国语学院：徐义云
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Exposition 说明文
一、什么是说明文？
说明文是客观阐释，是对客观事物的性质、形态、特征、结构、功能、成因、结果或发生发展过程的解释说明，以便让读者对事物的本质获得完整而清晰、客观准确的认识和了解。
说明文的目的是告知（to inform）。
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二、英语说明文的结构：

引入段 + 主体段 + 结尾段
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引入段。主要是提示文章的主题，向读者说明文章的主要内容、事物和对象。
主体段。一般由一段或若干段组成，主要是对文章的主题、论点、主要说明的事物或事理等诸方面，从不同的侧面、角度对说明对象进行分项具体的阐述、解说。
结尾段。主要是对说明对象进行总的概括性说明，以达到归纳文章重点和深化主题的作用。
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三、说明文的写作要求
说明文的重要特点是清晰。为达到这一目的，
需要做到以下几点：
1、限制说明的事物和范围，因为不可能在一篇短文中解
释太多的事物。
2、准备足够多的，确切的例子，进行阐述、例证。
3、用正确、恰当的顺序摆出事实、观点。
4、注意用词和句子的准确性。最后，尽可能使说明的内
容生动，有趣。
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四、说明文的采用的方法
举例
分类
比较与对照
因果分析
过程叙述
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Exposition
一）举例说明文
举例说明文使用例子阐明观点，这是最常见，往往也是最有效的阐释模式。不用例子确实难以写好任何文章。好的例子有助于作者清楚地表达思想，从而避免泛泛而谈。实例能使抽象的问题具体化，这样不但能引起读者的兴趣，还可以增强文章的说服力。一篇好的举例说明文应该做到以下2点：
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1）精心地挑选一些具体、典型、有趣，与题目密切相关的例子，例子可以是作者的亲身经历，也可以来自可靠的第二手资；
2）妥贴地编排例子。类似的、相关的例子应归在一起，并按照逐步推向高潮的递进顺序排列。
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例如： Elements and Compounds
Aluminum (AL), water (H2O), oxygen (O2) and carbon dioxide (CO2) are substances. Some substances are elements and some are compounds. Elements have only one type of atom whereas compounds have more than one type.
Aluminum is an element: it has only one type of atom (i.e. it has only aluminum atoms). Oxygen has only one type of atom, so it is also an element.
Carbon dioxide has two types of atom (carbon and oxygen), so it is a compound. Sulphuric acid (H2SO4) is also a compound: it has three types of atom (hydrogen, sulphur and oxygen), water is also a compound.
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(这篇短文通过举例的方法，对铝、氧、水、二氧化碳、硫酸等例子进行分析,通过铝元素、氧元素分别是由铝原子和氧原子组成的，而水是由氢和氧、二氧化碳是由碳和氧、硫酸是由氢、硫、氧组成的这种现象，最终说明了“元素是由一种原子组成的，而混合物则是由一种以上的原子组成”这一主题。文章短小清楚，使读者易于理解。)
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二）分类说明文
分类说明文是把复杂的说明对象,按一定的标准，分成若干类,然后再分别说明或描述各事物的特点和差异。在撰写分类说明文时应注意：
1）被说明的对象必须是同属不同类或同类不同种的事物，不同属，不同类的事物不能用分类法说明；
2）分类的标准必须统一，不可同时用两种不同的标准分类，也不可以中途变更标准。
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例 1 Musical Instruments
There are many different kinds of musical instruments. They are divided into three main classes according to the way that they are played. For example, some instruments are played by blowing air into them. These are called wind instruments（管乐）. In some of these the air is made to vibrate inside a wooden tube, and these are said to be the wood wind family. Examples of wood wind instruments are the flute, the clarinet（单簧管）and the bassoon（低音管）. Other instruments are made of brass, the trumpet and the horn, for example. There are also various other wind instruments such as the mouth-organ（口琴） and the bag pipes（风笛）.
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Some instruments are played by banging or striking them. One obvious example is the drum, of which there are various kinds. Instruments like this are called percussion instruments（打击乐器）. The last big group of musical instruments is the ones which have strings. There are two main kinds of stringed instruments（弦乐）: those in which the music is made by plucking（弹或拨） the strings, and those where the player draws a bow(琴弓）across the strings. Examples of the former are the harp and the guitar. Examples of the latter are the violin and the cello (大提琴）.
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(这是一篇分类说明文。在对说明对象进行分类时总要有一个标准，就是说我们是根据什么来分类的，比如在这篇例文中将乐器分类的标准是演奏方式，然后根据这个标准将乐器分为均等的三类：管乐器、打击乐器和弦乐器。如果任何一类还有次类，那么可以根据新的标准继续分类，比如以上例文中管乐器根据其制作材料还可以分为木管、铜管以及其它材质的。)
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例2： Plants and trees are provided by nature with four means of dispersing their seeds.
The first is wind dispersal. The seeds of some plants are too light that the wind may transport them easily.
Secondly, seeds are dispersed by birds and animals. Some seeds adhere to the fur of animals, and are shed as the animals move about. Others are transported by birds.

（to be continued)
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The third method is self-dispersal. The plant itself twists and breaks the walls of the fruit so that the seeds are thrown or shaken out, e.g. the pea, the bean, etc.
Finally there is water dispersal. The seeds float on the water either because they are very light, or because they contain air. The coconut may be transported to land hundreds of miles across the ocean in this way.
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（这篇文章短小，精练却很能说明问题。文章的引言段一句话就点明了主题：“大自然给植物提供了四种传播种子的方式。”后面的四段依次分别讲述了：风传播、鸟传播、自我传播和水传播。通过此文可以看出，运用分类的方式可使文章脉络清晰层次分明，使读者更加清楚地了解并记住文章所要说明的事物。）
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三）比较和对比说明文
比较对照是写说明文的常用方式。在大多数情况下，比较与对照是不能分开的。一篇文章中既可以比较对照两个或两个以上的事物，阐明它们所存在的相同点，也可以用同样的方法阐明它们的不同点。
写这类文章时应牢记以下原则：
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1) 比较对照只能在同类的(通常是两个)事物之间进行；
2) 比较对照说明文有两种模式：
同时比较： A1/B1, A2/B2, A3/B3 …
先后比较: A1,A2,A3/B1,B2,B3…
3) 比较对照的事物各自占的篇幅应大致相同，比较对照的项目也应一致；
4) 比较对照必须以有关的具体实例为依据；
5) 比较对照说明文通过指出两者的异同来阐明具体问题。
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Exposition
The Elderly
Although old people in the United States and in Japan are treated the same in some way, in other ways they are treated differently.
In both countries the elderly are shown respect. Young people will give them a seat on a bus or train or will open a door for them. In both countries older people may ride the bus or go to a show for less money than the young have to pay.
.
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Nevertheless, in Japan the elderly have the highest respect. Grandparents live with their families all their lives. They help to raise the grandchildren. If any one need advice, the first person to be asked is the grandfather, because he is the wisest. In the United States, the grandparents live with other old people in “Senior citizen” places. They see their grandchildren only on holidays or special times.
I think it is better for families to live together in companionship.
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四）因果分析说明文
所谓因果关系说明文包含有两个方面，一个是看到一种现象推断某成因，一个是根据某一现象的特点推测它可能的发展或者是它在某种条件变化下的可能结果。
分析原因和结果是个复杂的过程。写因果说明文时，切记以下几点：
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1）分析原因时切不可过于简单化；
2）尤其要注意不要犯逻辑错误；
3）要区分直接原因与间接原因,直接后果与间接后果以及主要原因与次要原因,主要结果与次要结果；
4）不要遗漏一系列原因和结果中的任何一个环节；
5）语言要客观,分析要有根据,事实要确凿。
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例如：Deserts are spreading very rapidly mainly for two reasons.
First, in some regions there are too many cattle, goats and sheep. These animals eat the plant which would keep the top soil from washing or blowing away. Next, in areas where people depend on wood for heating and cooking, trees are cut down. If these areas are overpopulated, every piece of burnable wood may disappear. Consequently, the deserts move in.
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(这篇短文先指出结果Deserts are spreading very rapidly，后分析原因，如牛羊过多导致绿草减少。人为乱砍滥伐，森林遭到破坏。原因分析真实可信，重点突出，给人留下深刻印象。)
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五）过程分析说明文
这一类型的说明文主要是分析具体的操作步骤，采用的顺序通常都是时间顺序，一些表示时间推移的词和短语是常用的，如：first, second, third, then, soon, now, next, at last, consequently, while, in ten minutes 等等。
例如：
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Exposition
How to Build a Camp Fire
There are several steps to build a camp fire. First, collect a good supply of wood, small branches and larger logs. Second, twist newspaper into small knots. Third, make a pile on the ground of several paper knots. Fourth, cover this pile with a few small branches. Lay the larger pieces of wood on the camp fire from different directions. Fifth, place logs and larger pieces of wood over the branches. Finally strike a match and ignite the paper at the bottom of the camp fire, lighting it in several paces, you will be rewarded with a roaring blaze.
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五、如何写说明文的引言段
写说明文通常要有一个概述用来提出主题。这个概述就是引言段的内容。
其写法是：
１）概述某一现象或事物、事理的基本特征 + 主题
２）概要介绍事物、事理的总貌或局部特征以引起读者求知的兴趣和积极性 + 主题
３）提供正确获取知识所必需的背景材料 + 主题
４）指出使对方认识事物，了解有关信息的目的、要求或依据等 + 主题
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Exposition
Example1:
How to Eliminate Stress (如何消除紧张）
As the pace of living continues to increase, more and more people are in the habit of rushing through life, especially in big cities. We know too much stress in not good to our health. Sometimes it can lead to poor performance and illness. Many ways can contribute to solving this serious problem, but the following may be most effective.
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Example 2
Why Do Many Tourists Like Visiting Museums?
Many people visit museums when they travel in an unfamiliar place. Even if they do not have enough time, they would rather visit a museum than any other scenic sports. There are many reasons for this phenomenon, but in general, they come down to three major ones.
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Example 3
Now, when a person is hunting for a job, there will always be a job interview, and the job interview has a lot of advantages. The interviewer and interviewee can know about each other through it.
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Example 4　
If there is an essay which tells the customer how to complain to the boss of a store when he bought a faulty item in the store, the beginning can be written as follows:
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When a consumer finds that an item she or he bought is faulty or in some other way does not live up to the manufacturer’s claim for it, the first step is to present the warranty(保单) or any other records which might help at the store of purchase. In some cases, this action will produce results. However, if it does not, there are various means the consumer may use to gain satisfaction.
紧接着,作者按先后顺序介绍了简单的、比较有效的、有效的和最有效的措施。说明的内容层层深入。因为有开头段总述，所以文章的过渡显得非常自然。
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六、如何写主体段
在这个阶段，我们应当用足够的细节、实例、事实来支撑
文章的主题。
采用的方法有：列举法、例证法、因果法、比较对照法、
分类法、程序法等。
写作的顺序有：
１）以时间为顺序，用于重点写事物变化过程的文章。
２）按空间顺序，用于介绍自然景物、名胜古迹的文章。
３）按主次轻重的顺序，用于重点解说事物效能、用途或全面介绍事物特点的文章。
４）按事理逻辑次序以及必须反映事物自身逻辑顺序的文章。
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How to Eliminate Stress (The body para.)
First of all, we must know ourselves well to lower our goal. The high goal is the main cause of stress. So we cannot set out our goal too high. Besides, we can slow down the pace of living to adjust our life and enjoy our leisure time, such as having some physical exercises, taking a walk and listening to music. All in all, relaxation is essential for a healthy mind and body. Finally, keeping in touch with your friends is also a good way, because when we are in the stress, we’ll feel upset. Thus, we should find friends to talk with. Then we will feel better.
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Why Do Tourists Like Visiting Museums?
For one thing, these p