在上一讲我们讲了主题句，推展句的写法；这一讲我们要进一步来谈一谈段落发展的几种手段以及结尾段的写法。

一、段落发展的几种手段

1． 列举法(details)

　　作者运用列举法，是通过列举一系列的论据对topic sentence中摆出的论点进行广泛、全面地陈述或解释，列举的顺序可以按照所列各点内容的相对重要性、时间、空间等进行。

　　Yesterday was one of those awful days for me when everything I did went wrong. First, I didn't hear my alarm clock and arrived late for work. Then, I didn't read my diary properly and forgot to get to an important meeting with my boss. During the coffee break, I dropped my coffee cup and spoilt my new skirt. At lunch time, I left my purse on a bus and lost all the money that was in it. After lunch, my boss was angry because I hadn't gone to the meeting. Then I didn't notice a sign on a door that said "Wet Paint" and so I spoilt my jacket too. When I got home I couldn't get into my flat because I had left my key in my office. So I broke a window to get in－and cut my hand.

　　根据本段主题句中的关键词组everything I did went wrong，作者列举了8点内容，分别由first, then, during the coffee break, after lunch time等连接词语引出，使得该文条理清楚、脉络分明、内容连贯。

　　常用于列举法的过渡连接词有：for one thing , for another, finally, besides, moreover, one another , still another, first, second, also等。

　　2. 举例法(example)

　　作者通过举出具体事例来阐述、说明主题句的内容，严格地讲，举例法也是列举法的一种，它们的区别在于：列举法侧重罗列事实，所列事实力求全面；而举例法侧重通过举出典型事例来解释作者观点，且事例可多可少。

　　我们来看下面这个用举例法展开的段落。

　　There are many different forms of exercises to suit different tastes. For example, those who enjoy competitive sports may take up ball games. For another example, if they prefer to exercise alone, they can have a run or take a walk in the morning or in the evening. Besides, people can go swimming in the summer and go skating in the winter. In short, no matter what their interests are, people can always find more than one sports that are suitable to them.

　　本段采用了三个事例来说明主题句中的关键词组different forms of exercises，这三个例子分别由连接词for example, for another example 和besides引出，最后由引导的结尾句总结全段内容。

　　举例法中常用的连接词有：for example(instance), one example is, besides, furthermore, moreover, in addition等。

3. 叙述法(narration)

　　叙述法发展段落主要是按照事物本身的时间或空间的排列顺序，通过对一些特有过渡连接词的使用，有层次分步骤地表达主题句的一种写作手段。用这种方法展开段落，作者能够清楚连贯地交待事物的本末，从而可以使读者可以清晰、完整地理解文章的含义，例如：

　　In the flat opposite, a woman heard the noise outside. When she looked out through the window, she discovered that her neighbour was threatened by someone. She immediately called the police station. In answer to the call, a patrol police car arrived at the scene of the crime quickly. Three policemen went inside the flat at once, and others guarded outside the building to prevent anyone from escaping.

　　这段是按照事物发展的先后顺序，叙述从发现案情、报警、到警察赶到、包围现场的过程。全文脉络清晰，叙述的层次感强，结构紧凑。

　　常用于叙述法中的过渡连接词有：

first, an the beginning, to start with, after that, later, then, afterwards, in the end, finally等。

4． 对比法或比较法(comparison & contrast)

　　将同类的事物按照某种特定的规则进行比较分析是一种常用的思维方法。通过对比，更容易阐述所述对象之间的异同和优缺点，例如：

　　The heart of an electronic computer lies in its vacuum tubes, or transistors. Its electronic circuits work a thousand times faster than the nicer cells in the human brain. A problem that might take a human being a long time to solve can be solved by a computer in one minute.

　　在这段文字上， 作者为了突出电子计算机运行速度之快，首先将它与人脑进行了比较， "---a thousand times faster than ---" ;而后，又将这一概念具体到了 ＂a problem＂上，通过对比使读者从 "---a long time ---in one minute＂上有更加直观的认识。

　　常用于对本法或比较法上的过渡连接词有：than, compared with等。

5． 分类法(classification)

　　在阐述某一概念的段落中，常用分类法。通过对概念中所包括的事物进行分门别类，分别加以叙述，使读者有更为清晰的认识，如：

　　Ever since humans have lived on the earth, they have made use of various forms of communication. Generally, this expression of thoughts and feelings has been in the form of oral speech. When there is a language barrier, communication is accomplished through sign language in which motions stand for letters, words and ideas. Tourists and the people unable to hear or speak have had to resort to this form of expression. Many of these symbols of whole words are very vivid and exact and can be used internationally; spelling, however, cannot. Body language transmits ideas or thoughts by certain actions, either intentionally or unintentionally. A nod signifies approval, while shaking the head indicates a negative reaction. Other forms of nonlinguistic language can be found in signal flags, Morse code, and picture signs.

　　在该段中为了说明topic sentence中的 ＂various forms of communication＂，作者将其分为oral speech, sign language, body language及other forms of nonlinguistic language，并逐加阐述。

　　采用这种方法的段落并没有标志突出的连接词，所述各项均为平行并列关系，所以没有明显的主次之分。

6．　因果分析法(cause and effect )

　　在阐述某一现象的段落中，常采用因果分析法。例如：

　　The role of women in today's society is changing. One reason is that women have begun to assert themselves as independent people through the women's movement. Also, women are aware of the alternatives to staying at home. Another reason is that increasing numbers of women who enter new fields and interests serve as role models for other women. Moreover, men are becoming more conscious of the abilities of women and have begun to view their independence positively.

　　本段中，主题句提出了一种社会现象，推展句则对产生这种现象的原因作出各种解释。 常用于因果分析法的连接词有：because, so, as a result等。

7． 定义法(definition)

　　在科普文章的写作中，定义法是必不可少的。通过下定义，可以使读者对该事物有一个更直接的认识。

　　Automation refers to the introduction of electronic control and automation operation of productive machinery. It reduces the human factors, mental and physical, in production, and is designed to make possible the manufacture of more goods with fewer workers. The development of automation in American industry has been called the "Second Industrial Revolution".

　　这一段文字使我们了解了 ＂automation＂ 和 ＂Second Industrial Revolution＂ 两个概念，分别由 ＂refers to" 和"been called＂ 引出。

　　常出现在定义法中的词语有：refer to , mean, call等。

8. 重复法(repetition)

　　句子的一部分反复出现在段落中，这就是重复法。它往往造成一种步步紧逼的气氛，使文章结构紧凑，有感染力。比如：

　　Since that time, which is far enough away from now, I have often thought that few people know what secrecy there is in the young, under terror. I was in mortal terror of the young man who wanted my heart and liver; I was in mortal terror of my interlocutor with the iron leg; I was in mortal terror of myself, from whom an awful promise had been extracted;---

　　该段中反复应用了I was in motal terror of …我经常处于恐怖之中。

　　以上， 我们结合具体文章讨论了展开段落的几种方法。在实际写作中，我们往往不必拘泥于一种写作方法，而是将若干方法穿插在一起，使文章有声有色。