分类文(classification)一种按一定标准和原则将人或客观事物分门别类，以总结各类事物共同特征的篇章形式。
分类是人类认识自然的主要方法，是人类按自己的原则和需要对各种事物进行重新分配组合或排列的思维过程。分类文就是对这一人类思维活动的文字体现。分类文同分析文相似，也注重事物的类别和特征，但与分析文又有着本质的不同。前者重"类"，即注重事物建立在一定特征或标准基础上的类别；后者则重"析"，即对某一事物内在的不同因素加以分析。分类文的对象通常为一定数量的人或物，而分析的对象则多为单一的人或物。
阅读分类文先要弄清楚被分类的对象，不同的实物有不同的类别，分类方法也不一样：图书馆有分类目录，报纸有分类广告。读者是作者在分类文中决定其分类方法和层面的决定因素。分类文往往以提供信息为主要目的，作者在多大程度上对事物进行分类，这主要取决于读者的主观需要、知识结构和专业兴趣；分类文最重要的一点是必须阐明对某一种事物的分类原则。上海道正认为可以根据完全不同的标准和原则把汽车划分成各种不同的类别，如国别、厂家，型号，功能，大小，豪华程度，燃料等不一而足。所谓分类原则和标准，就是一类事物所共同具有的特征。如果对一筐苹果进行分类，我们可以以颜色为标准：
Apples
|
－－－－－－－－－－－－－－－－－－－－
| |||
red yellowGREen yellow-green
apples apples apples apples
或者根据味道：
Apples
－－－－－－－－－－－－－－－－－－－－
| ||
sweet sour tart
apples apples apples
1. a, Clouds are classfied cumulus and stratus accord
在确立任何分类标准或原则时，根据上海道正学校教学与研究,作者一般都必须遵循以下四项原则：
1．必须根据共同特征进行分类；
2．不同层次的分类遵照不同的原则；
3．在一个分类层面上，一个事物只属一类
4．各个层面的分类必须彻底。
示例分析
根据以上原则，在任何一篇分类文中的主旨句和段落的主题句的主要内容就是阐明分类的事物、分类原则和类别，如下例各句就是典型的主旨(题)句：
1. a. Clouds are classfied cumulus and stratus according to how they are formed.
b. Clouds are classified by altitude into four families:high clouds, middle clouds, low clouds, and towering clouds.
c. It is possible to define five general types of audience of any rock-and-roll concerts on the basis of dress,manner, consumption, age, and music taste.
d. The marijuana user, on any given campus, may be placed in one of three categories: a dabbler, a user, and a head.
e. What we see growing around us is a sort of'social stratification in which the highbrows are the elite, the middlebrows are bourgeoisie, and the lowbrows
are hoi polloi.
f. In the subsurface component of any terrestrial habitat the organisms are divisible into three groups on the basis of their size. The groups are (1) the microbiota, (2) the mesobiota, and (3) the macrobiota.一般来说，分类文(段)具有以下基本框架：
首段 Introduction(含点明分类标准和类属的主旨
(题)句)
类型1 Type 1
类型2 Type 2
类型3 Type 3，4，5，……
尾段 Conclusion下例就是按这一框架写成的段落
(主题句)There are three kinds of book owners according to the way they deal with their books. (Type 1: nonreaders) The first has all the standard sets and best-sellers unread, and even untouched. (This deluded individual owns woodpulp and ink, not books.) (Type 2: occasional readers) The second has a GREat many books--a few of them read through, most of them dipped into, but all of them as clean and shiny as the day they were bought. (This person would probably like to make books his own, but is restrained by a false respect for their physical appearance. )(Type 3: devoied readers) The third has a few books or many--every one of them dog-eared and dilapidated, shaken and loosened by continual use, marked and scribbled in from front to back. (This man owns books) (Conclusion) In a word, these categories of books owners are different in the number of books you own and in the extent they make use of their books.2. The Common Cold
These home cures generally follow one of three distinct courses, and as each reflects the psychology of the suffcrer,let us examine them in detail. They are: (1) the Fresh-Air
Treatment; (2) the Scientific Attack; (3) the Coddle.
The Fresh-Air Treatment is practiced only by those large redfaced men in check suits who look you in the eye,slap their chests, and declare they've never owned an overcoat or been to a doctor in their lives, as if claiming freedom from original sin. They have a simple attitude to illness: it's all "psychological""from smallpox to fractured femurs. But they are only human, and in time claimed by both death and colds.
The first sneeze affects them like a starter's pistol:they tear off their ties and waistcoats, stamp around the house throwing open the windows, jump into a cold bath,and upset their wives by doing breathing exercises all night in bed. The discomfort in which they wallow for a fortnight makes no difference to the course of the disease, but by rendering their surroundings unfit for human habitation, theyrarely manage to infect anyone else.The Scientific sufferer takes a much calmer view of his cold. He is generally a precise, clerkish man, who files the medical articles from the Reader's Digest and reads the patent-medicine advertisements like a girl looking into a bride-shoP window. During the winter he gargles for five minutes with antiseptic night and morning, wears wool next to the skin, and eats sufficient calcium to keep a schoolroom in chalks. As soon as his nose starts to run he calls at the druggist's and arrives home with his brief case clinking gently with small bottles. He announces to his wife: "Think I'm getting a touch of a cold, re'dear," as though he were having a baby. He makes for the bathroom and unpacks his bag, which is filled with cough mixtures, fever pills, throat lozenges, nose drops, eye lotions, and liniments. He sets the bottles carefully on the shelf and works his way through them thoughtfully and solemn drinks in a strange port.
This type of invalid follows the directions on the label with scientific precision: if it orders "An egg-cupful fourhourly," he fetches an eggcup; if it says "Rub on the chest till it stings," he scrapes away until his skin begins to peel.He then has a mustard bath, soaks his feet in salt water,puts on two pairs of flannel pajamas, and goes to bed with The Household Doctor. No physician ever watched the recovery of a wealthy patient more sadly than he notices his own returning health. For, once he has caught his cold, he does not lightly let it go. From October to May he richly justifies the famous mistranslation of voici I'anglais avec son sangfroid habituel -- here comes the Englishman with his
usual bloody cold.
The Coddler is usually a woman, with a far more fuzzy idea of her internal organs than the Scientific sufferer. Since girlhood she has been told that she must Take Care of a Cold or it will turn into Something Else; her life passes in a terror of Germs, which she imagines as small GREen animals,, with red eyes and long teeth, that hide under, the dustbin. Before she has blown her nose twice, the Coddler has phoned her husband's office and all her friends to explain that she has a cold, in the tone of someone announcing that smallpox has just broken out. She then pours herself a large Scotch, lights a fire in her bedroom, piles extra eider downs on the bed, shuts the windows, rubs herself all over with camphorated oil, phones out for grapes, calf's foot jelley, chicken essence, barley water, the other prerogatives of illness, shifts the television upstairs, collects all the magazines in the house, and goes to bed. She stays there for a fortnight, her family fetching her egg-and-milk every hour.
People suffering from a cold behave quite differently just because they have entirely different idea about the disease.
by Richard Gordonly, like a sailor trying out the
(From Rhetoric and Literature)
