一、时间法
在叙述一个故事或者一系列事件时，通常按事件发生的先后顺序排列句子。在说明文中叙述一件事应该遵循的程序或步骤时，也常用时间顺序法。看下面的例子：
A friend in need is a friend indeed.
患难见真情。After lunch, while the other girls were sunbathing, Pat and I returned to the water. Soon cramps spread from my stomach to my legs. Immobilized by pain and fear, I yelled for help. My friend thought I was joking: so she ignored me. However, Sister Theresa came to my rescue when she noticed my plight. She pulled me out of the water and administered resuscitation. When regaining consciousness, I realized how close I had come to death. My experience with near death reminds me every day how close we all are to death in our daily lives.
在这个段落里，作者用了after lunch; while...; soon; when...等时间连接语按时间的先后顺序记叙了一件发生在午饭后的事。
There are four separate stages in making bread. The first stage begins by mixing yeast with warm water. This mixture is then added to half the amount of flour. The resultant batter mixture is then left for an hour. At the next stage the rest of the flour is added to the risen batter mixture, along with salt and oil. The main step in the second stage is a thorough kneading of the dough, after which it is left to rise. The third stage involves shaping the dough into loaves; the shaped loaves are then put into bread tins and left to ‘prove’ (rise). In the final stage the bread is cooked in a hot oven. The whole process of breadmaking finishes when the bread is taken from the oven and left to cool on wire racks.
这个段落采用时间顺序法描述了做面包的的过程。作者用了The first stage begins by..., At the next stage..., The third stage involves... 和In the final stage... 等连贯性词语详细地按照先后顺序介绍了四个步骤。
二、空间法
空间顺序指按物体的空间位置（自左至右，由近到远，由上至下，由下到上，由里到外，由外到里，由中间到两边等顺序）来展开段落。如：
The room was disgusting. By the far window was a trash can piled high with crumpled papers. In the middle of the room was a gaudy, roundsize bed littered with rotting fruit peels. The path between the bed and the doorway, where I was standing, was choked off by heaps of dirty clothes and old newspapers.
这个段落以空间顺序法描写了一个房间。先从描述远处的窗子开始，接着是房间中央，最后到作者所站的地方，由远到近地将房间里的一切描绘了出来。
Great Britain is an island that lies off the northwest coast of Europe. The nearest country is France which is 20 miles away from which Great Britain is separated by the English Channel. The island is surrounded by the Atlantic Ocean to the west, and the North Sea to the east. It comprises the mainland of England, Wales and Scotland. Scotland is in the North, while Wales is in the west. Ireland, which is also an island, lies off the west coast of Great Britain. It consists of Northern Ireland and the Irish Republic. Great Britain together with Northern Ireland constitutes the United Kingdom. Thus, the United Kingdom is composed of four parts. The largest of these is England which is divided into 43 administrative counties. The capital city is London which is situated in southeast England.
这个段落主要是采用由外到里的空间顺序法进行描写的。先从外围描述大不列颠的地理位置，接着从内部仔细介绍它的各个组成部分—— 英格兰、苏格兰和威尔士的相对位置，同时描述了爱尔兰岛的相对位置，最后作者又特意指出英国首府伦敦的地理位置。
三、列举法
列举法是通过列举具体的细节来进一步说明主题句所表达的主导思想，展开段落。列举法如果使用得当，能增强文章的说服力，使文章显得条理清楚。用列举法发展段落时，主题句常包含表示数量的词，如：several, many, some, four 等。列举细节时，可以根据各种内容的相对重要性，按一定的逻辑顺序排列。
Strike the iron while it is hot.——趁热打铁。请看下面的例子：
Social activities benefit us in many ways. To begin with, these activities can widen our knowledge, because we can learn what we cant from our books. Second, these activities can serve as a bridge between theory and practice, because we can learn how to put our book knowledge into practice. Lastly, these activities can enrich our experience, in that we can get to know the society well so that we can adapt to it easily when we graduate.
本段的第一句是段落主题句，in many ways在这里为下面的列举作好了铺垫。作者用了to begin with, second和lastly作为连接语，条理清楚地列举了社会活动有益的三个方面。
四、举例法
举例法是一种常见的展开段落的方法，它是用典型、具体而生动的事例来证明、阐述一个观点，支持主题句，使段落主题句的抽象意思具体化，使文章通俗易懂并具有说服力。但是，在写提供实例的段落时，必须精选例子，要作到恰如其分、准确地说明问题。
请看下面的例子：
Many old buildings in cities are still being found useful. In several cities, old buildings that were no longer being used have been converted to a variety of useful structures. For example, one school building was changed into ninetynine rental units for elderly and low income residents. In Baltimore, Maryland, six schools were converted into 132 units with the help of a fourmilliondollar city bond financing arrangement. “School House 77” in Boston utilizes three recycled elementary schools and an abandoned instrument factory. All these examples show how cities are using unneeded schools, police stations, libraries, and boardedup factories that are structurally sound and even architecturally interesting buildings.
本段的第一句是段落主题句，指出在城市里有许多旧楼还在发挥着作用。这里的“作用”是比较抽象的，不容易写得很充分。但是作者用一些实例（如将旧校舍改建成住房提供给低收入人群等）来加以说明，主题思想就较为容易和直观地表达出来了。
It takes two to make a quarrel.——一个巴掌拍不响。 It is very difficult to evaluate another persons performance objectively. For example, Linda recently wrote irresponsible remarks about her instructor because she was failing the course. Her friend Jack wrote a marvelous description of the same instructor because he was receiving an A in the course. Both Linda and Jack were not fairly evaluating the instructor. They were influenced by the grades they were earning and were biased in their judgment.
这个段落的第一句是主题句，说明人们很难做到客观地评价另一个人的作为。接着用Linda和Jack两个例子来支持这一观点，展开段落。例子使用贴切典型，恰如其分。
五、对比法
对比法是指通过叙述或描述两种或两种以上的相关事物之间的相同（相似）的地方或不同之处来表达主题。采用对比法展开段落主要通过两种途径：一是先叙述对比双方的一个方面的全部细节，然后再叙述另一个方面的全部细节；另一个途径是对逐个问题进行双方面的比较。
请看下面各例：
Why do so many graduates gravitate into business instead of into teaching? Part of the reason is the everwidening pay gap between these two professions. A secretary, an office clerk or a bank employee can earn monthly income as high as RMB 2，000, and when one is promoted to the position of a business executive or manager, the salary is even higher. But a college graduate with a masters degree can only get a salary of RMB 1，000 per month for his teaching job. No wonder, college graduates are attracted into more lucrative（赚钱的，有利润的） fields.
本段的主题是为什么那么多的大学毕业生从商，而不从事教学工作。作者运用对比法，说明由于两种职业之间存在着越来越大的收入差异，所以有好多学生毕业后选择从商，而不选择从教。
A single spark can start a prairie fire.——星星之火，可以燎原。There are striking similarities between two of the most popular U.S. presidents, Abraham Lincoln and John F. Kennedy. Both men had their elections legally challenged. Lincoln and Kennedy are both remembered for their sense of humor, as well as for their interest in civil rights. Lincolns secretary was Mrs. Kennedy; Kennedys secretary was Mrs. Lincoln. Neither man took the advice of his secretary not to make a public appearance on the day on which he was assassinated. Lincoln and Kennedy were both killed on Friday in the presence of their wives. And finally, the same caisson（弹药车） carried the bodies of both men in their funeral processions.
本段采用对比法通过第一种途径展开段落。这里，作者将美国历史上两位伟大的总统林肯与肯尼迪从六个方面作了比较，描述他们的相似之处。
六、分类法
分类法是按一定标准对事物进行归类的一种段落发展方法。通过分类，可以使文章脉络一目了然。例如：
Astronomers have been able to classify stars according to color. They have discovered that stars with different colors have different sizes, and their surface temperatures are also different. The larger a star is, the higher surface temperature it has. Stars are generally divided into five kinds: blue, white, yellow, orange and red. Blue stars are the largest ones, with a diameter of 16,000,000 kilometers. Their surface temperature is also the hottest, as high as 25,000 degrees centigrade. White stars come next, whose diameter is 2,700,000 kilometers and whose surface temperature is 11,000 degrees centigrade. Then there are yellow stars, 1,600,000 in diameter and 6,000 degrees centigrade in surface temperature. Orange stars are still smaller. They have a diameter of 1,000,000 kilometers and a surface temperature of 5,000 degrees centigrade. The smallest kind of stars appears red in color. Their diameter is only onetwentieth of that of blue stars, that is, 800,000 kilometers, and their surface temperature is only 3,000 degrees centigrade.
One’s sin will find one out.
坏事终归要败露。 本段落的第二句话是段落主题句，说明不同颜色的星球其大小及表面温度各不相同。本段落分类标准非常清楚。段落一开始就指出星球可以按颜色进行分类。后来又明确指出星球一般被分成五种类型：兰、白、黄、橙和红色。接着，作者运用分类，清楚地层层展开，发展段落。
There are two kinds of sports: “amateur” and “professional”. Amateur athletes do not receive money for competing in sports. Olympic athletes, for example, are amateurs. They do not receive money. Professional athletes, on the other hand, do earn money. Some professional athletes earn a million dollars or more a year. They need this money to support themselves and they can save some for their future.
本段的主题句也在段落开头，指出运动有两种形式：业余的和专业的。然后，作者采用分类法发展段落，分门别类地对业余类（amateur athletes）和专业类（professional athletes）进行解释说明，使段落主题更明确地展示在读者面前，段落层次清楚，中心思想统一明了。
Examinations fall into three kinds. One is the machinescored “objective” type. In an objective test, the students answer questions by deciding on best choice among a number of alternatives given. Another is the “completion” type. This kind of examination requires the students to add a word or phrase to complete a sentence. And the third type is the essay examination, in which the students are asked to write a composition on a given topic. All these kinds of examinations are designed to reveal what a student may have learned in any particular course.
本段采用分类法来展开段落。主题句在段落开头，指出“考试可分三种类型”。然后，作者运用One is the machinescored “objective type”, Another is the “completion type”,“And the third type is the essay examination” 来清楚地将考试分类阐述，段落脉络一目了然，层次十分分明。
七、定义法
定义法是通过简单易懂而且准确的语言阐明某事物的性质和特征来发展段落，使读者对某事物比较抽象的或是难以把握的一些特征有一个较清晰的认识。定义法常用于说明、描写和论证，以提供更多的具体解释来说明某一概念或术语。
请看下面的例子：
Love is a very general term. It refers to a strong feeling of fondness for another person. It can happen between people of the opposite sex or between members of a family. No matter where it happens, love can always bring happiness to people.
这也是采用定义法发展段落的好例子。段落一开始，作者先指出，爱是一个常见的字眼，意义很泛。紧接着用It refers to ...来对爱(love)进行定义解释，清楚简单，意思明白。
Poetry is a branch of literature which explores ideas, emotions, and experiences in a distinctive form and style. Poetry, sometimes called “verse”, depends greatly on the natural rhythms and sounds of language for its special effects. Poetry, even more than prose (all other writings), depends on precise and suggestive wording. In other words, a poem says much in little space. Poetry differs from prose in obvious ways, also. Most often the first word of every line begins with a capital letter, even in the middle of a sentence. Poems sometimes contain rhyme, and often they have a particular rhythm, like music.
本段通过下定义的方法说明什么是诗歌。段落一开始就指出诗歌是一种文学形式。作者在段落首句里用一个which引导的定语从句直接对Poetry进行定义、解释。后来，还利用同散文（prose）的简单对比，将诗歌的特点淋漓尽致地展示给读者。
A good name is better than riches.——声誉胜于财富。
八、因果法
因果法是说明事态发展的原因和结果之间联系的，常用在说明文或议论文中。可以先讲原因，后给结果，也可以先给结果，后讲原因。这要视实际需要而定。也有一些段落结果是显而易见的，就集中说明原因；有的段落正好相反，就集中说明结果，因为原因不言自明。
请看下面的实例：
Homes that are improperly insulated may cause problems for their habitants. First of all, it will cost more to heat such a house than one that is well insulated. Second, it will waste energy. Third, it will make the house uncomfortable to live in because drafts or cold air is able penetrate the poorly insulated walls. Also, the poorly insulated walls could cause the inhabitants to have more colds, a health problem that results in higher expenses for doctors and medicine.
本段第一句是主题句，指出导致problem for their habitants 的是homes that are improperly insulated。然后集中笔墨阐明结果，在这里即problems。
So why do manufacturers keep on designing and producing VCRs that are awkward to use if the problems are so obvious? First, the problems we notice are not obvious to technically minded designers with years of experience and trained to understand how appliances work. Secondly, designers tend to add one or two features at a time to each model, whereas you and I face all of a machines features at once. Thirdly, although finding problems in a finished product is easy, it is too late by then to do anything about the design. Finally, if manufacturers can get away with selling products that are difficult to use, it is not worth the effort of any one of them to make improvements.
段落以问句开始——为什么生产厂家继续设计和生产那些难用的录像机？问句之后，作者列出了四个原因。
九、综合法
综合法是指根据行文的需要采用两种或两种以上的方法来展开段落的写作方法。
请看下面的例子：
Haste trips over its own heels.——忙易出错。Balloons have been used for sports for about 100 years. There are two kinds of sports balloons: gas and hot fire. Hot balloons are preferred by most balloonists in the United States because of their safety. They are also cheaper, and easier to manage than gas balloons. Despite the ease of operation on a balloon, pilots must watch the weather carefully. Sport balloon flights are best early in the morning or late in the afternoon, when the wine is light. Over the years balloonists have tried unsuccessfully to cross the Atlantic Ocean. It wasnt until 1978 that three American balloonists succeeded. It took them just six days to make their trip from their home in the United States to Paris, France. Their voyage captured the imagination of the whole world.
这里的第二句话是段落的主题句。本段首先运用分类法，说明用于运动的气球可以分为两类：充气气球和热气球。接下来用了比较法，说明热气球要比充气气球安全；同时，作者还用了因果分析法说明热气球以其安全性能强为美国人青睐。整个段落综合运用了分类法、比较法，以及因果分析法，但是主题思想明确。各种展开段落的方法综合在一个段落里全部是为表达主题服务的。
综合法需要具体情况具体分析地使用，千万不可“眉毛胡子一把抓”，或者信笔胡写，一定要注意围绕主题句，以说明段落中心思想为前提，保持段落意思的一致性和连贯性。
