就“说明对象”而言，英语说明文可分为对“客观具体事物”的说明和对“主观抽象观念”的说明两大类，比如：对“LASER(激光)”、“Computer Problem of Year 2000(计算机2000年问题)”等等的说明都是对客观或者具体事物的说明，而“The Successful Interview(谈成功的面试)”、“How to Write Good English Composition(如何才能写好英语作文)” 等是对主观抽象观念的说明。对我们中学生朋友来说，在汉语说明文的教学中似乎比较侧重前者，即解释客观具体事物的说明文。但在英语说明文中，阐述和说明 “主观抽象观念”的说明文占了很大的比重，其中有些类似汉语中的议论文。但是无论是对“客观具体事物”的说明还是对“主观抽象观念”的阐述，英语说明文从结构上看大致可分为三个部分：第一部分一般是文章的第一段，提出文章的主题，也就是说，文章想要阐述、说明的主要内容;第二部分是文章的主体，可由若干个段落组成，对文章的主题进行展开说明;第三部分是结尾段，对文章的主题作归纳总结。从英语说明文的结构可以看出，要写好英语说明文的关键在于第二部分如何对文章主题进行展开说明。在英语中，常见的用来展开文章主题的方法有下列几种：
Early rising (早起) is helpful in more than one way. First， it helps to keep us fit (健康)。 We all need fresh air. But air is never so fresh as early in the morning. Besides， we can do good to our health from doing morning exercise (做早操)。
Secondly， early rising helps us in our studies. We learn more quickly in the morning， and find it easier to remember what we learn in the morning.
Thirdly， early rising enables (使能够) us to plan the work of the day. We cannot work well without a good plan. Just as the plan for the year should be made in the spring， so the plan for the day should be made in the morning.
Fourthly， early rising gives us enough time to get ready for our work， such as to wash our faces and hands and eat our breakfast properly.
Late risers may find it very difficult to form the habit of early rising. They ought to make special efforts to do so. As the English proverb says，“Early to bed and early to rise， makes a man healthy， wealthy and wise.”
There are several good reasons why we should learn a foreign language. First of all， …Secondly， …And finally， …
We should try our best to plant more trees for several good reasons First of all， …Secondly， …And finally，
举例法是用具体的例子来说明我们要表达的意思，常用for example， for instance， still another example is…等词语引出。下面这篇学生作文就是用举例法写成的：
It is impossible to keep in good health unless we take enough recreation (娱乐)。 The mind， too， needs change to make it fresh and vigorous (有活力的) There is much truth in the old saying， All work and no play makes Jack a dull boy.“
There are many games which boys and girls can play after their school work is done， for instance， football， tennis， and kite-flying. Other examples of recreation are boating， fishing， gardening， cycling， walking， chess-playing， and reading. Persons who sit much at their business should take a kind of recreation that will supply their muscles (肌肉) with exercise. Those who spend most of their time in the open air and do manual work (体力活) should adopt (采纳) reading or some other quiet form of recreation.
Cycling is said to be an important means of recreation， but many persons foolishly tire out themselves by cycling too much. The same may be said in regard to football. Tennis is a pleasant form of recreation. Many persons take great delight in boating. Fishing requires much patience， and there is much danger of taking cold by sitting still on a cold day too long. A good brisk (轻松) walk is one of the finest forms of exercise. For persons engaged in outdoor labor， chess-playing is another excellent form of recreation.
3.比较法(comparison and contrast)
From Paragraph to Essay
Although they are different in length (长度)， the paragraph and the essay are quite similar in structure (结构)。 For example， the paragraph starts with either a topic sentence (主题句) or a topic introducer followed by a topic sentence. In the essay， the first paragraph sets up the topic focus (主题所在) Next， the sentences in the body of a paragraph develop the topic sentence. Similarly， the body of an essay consists of a number of paragraphs that discuss and support the ideas given in the introductory (引导的) paragraph. Finally， a concluding sentence (结束句) ——whether a restatement， conclusion， or observation——ends the paragraph. The essay， too， has a concluding paragraph which ends the essay logically and satisfactorily. Although there are some exceptions (例外)， most well written expository (说明文的) paragraphs and essays are similar in structure.
可以看出，在比较相同点的时候，常用到similarly，also，too，in the same case，in spite of the difference等这样的词语。
European Football and American Football
Although European football is the parent of American football， the two games show several major differences. European football， sometimes called association football or soccer， is played in 80 countries， making it the most widely played sport in the world. American football， on the other hand， is popular only in North America (the United States and Canada)。 Soccer is played by eleven players with a round ball. Football， also played by eleven players in somewhat different positions (位置) on the field， is played with an elongated (拉长的) round ball. Soccer has little body contact (接触) between players and therefore needs no special protective equipment. Football， in which players make the greatest use of body contact to stop a running ball-carrier and his teammates， needs special protective equipment. In soccer， the ball is advanced toward the goal by kicking it or by butting (顶) it with the head. In American football， on the other hand， the ball is passed from hand to hand or carried in the hands across the opponent's (对手) goal. These are just a few of the features which distinguish (区别) association and American football.
这是一篇用比较不同点的手法写的说明文。从文章中可以看出：however，on the other hand，in contrast，but，nevertheless等表示转折的词语常用来引导对不同点的比较。
A bat is a small mouse-like animal that flies at night and feeds on(以……为食品)fruit and insects but is not a bird.
其实，在英—英词典中，对英语单词的英文解释就是定义法的典型例子。比如，看看Longman词典对student和teacher的定义是很有意思的：A student is a person who is studying at a place of education or training. A teacher is a person who gives knowledge or skill to sb. as a profession (专业)。
5.顺序法(sequence of time， space and process)
Coal underwent (经受) many changes before it became the bright， brittle (脆的)， black substance which we now use. During ancient times (在上古时代)， when the earth enjoyed a very warm and wet climate， the land was covered with large forests and big plants. As time went on， the ground changed and began to sink (下沉) a little. These very large numbers of trees and vegetables received a deposit (沉淀) of sand and clay. This layer of sand and clay pressed upon the layer beneath and prevented it from contact with air. These trees and plants received the pres sure and changed its appearance.
Generations after generations (几世纪后)， as the ground kept gradually sinking， another layer of sand and clay was again deposited (积聚) above the layers already formed. A great pressure was thus exerted (作用) and the peat (泥煤) was changed into the black and brittle substance which is known as coal.
Coal is a kind of mineral which is formed by nature as above stated. It is an important industrial material and is chiefly used as fuel. It is very valuable in the industrial world. The place where coal deposit is called a coal mine (煤矿)。 In China， coal mines are largely found in the north-west part of the country. Shanxi is a famous province for producing coal. It has the most coal of China.
分类法是将写作对象进行分类说明的一种写作手法。比如：著名的英国哲学家弗朗西斯·培根(Francis Bacon)在其脍炙人口的《谈读书》(Of Studies)一文中就用到了分类法：
Some books are to be tasted， others to be swallowed， and some few to be chewed and digested， that is， some books are to be read only in parts， others to be read， but not curiously， and some few to be read wholly， and with diligence and attention. Some books also may be read by deputy， and extracts made of them by others; but that would be only in the less important arguments， and the meaner sort of books…