叙述文引入段的一般结构：叙述事情或事件引入+叙述事情或事件的基本目的或意义。
语例：
（1）A Visit to Rural Kenya
At the end of July 1995， I boarded a plane that would take me from my home in Cincinnati， Ohio， to Nairobi， Kenya.My parents had always wanted to take our family abroad， but when my mother signed a contract to work for the U.S.Agency for International Development in Kenya， plans materialized， and we were soon on our way to an exotic year in Africa.
（2）When I think of Georgetown University， I think of Washington and world affairs.I do not know yet exactly what type of professional career I will pursue after schooling， but I do know that I wish to be inter-nationally aware and involved， and that Georgetown would provide me with a solid foundation for that goal.(入学申请)
说明文引入段的一般结构：说明的对象引入+说明主题陈述。说明的对象引入在于告诉读者，作者拟就什么内容进行说明，说明主题陈述则在于告诉读者，作者拟就说明对象的哪个或哪些方面进行说明，以及作者拟大致采用什么方式如比较说明、对比说明、举例说明、操作或使用过程等进行说明。
研究论文属于比较规范和专业的文本，因此，研究论文的引入段的结构相对而言要复杂一些。研究论文的引入段一般包括以下几部分：引入所要研究的问题、已有的研究情况、尚未研究或尚需进一步研究的问题、研究的目的、研究的价值意义或论文预计的主要结构情况。
语例：
一篇论文题目为On Foreign Language Learner Errors的引入段。
Introduction
In the area of foreign language teaching， there have been some theories in which foreign language learner errors are analyzed， and diverse methods of dealing with them are suggested.These theories， however， offer different or even contraditory views on errors and completely different strategies in dealing with them.As a result， many foreign language teachers in China feel puzzled when facing their students' errors.Therefore， it is necessary to make still further research on the domain of error analysis and find proper error-treating ways in China where the number of foreign language learners， already great， is rising.
英语书信引入段的一般结构：写信原因+写信目的或者写信的原因或目的。
语例：
（1）
Dear Mr.President，
I'm very lucky to attend this world-famous university， but I'm afraid I'm not content with the canteen service on campus.(原因)
…
（2）
Dear Sir，
A recent advertisment in the TV Times magazine asks people to consider emigrating to Austria.I would be very grateful if you could give me more information about the possibility of emigrating， particularly information about the help you could offer.（原因和目的）
…
（3）
Dear Mr.Wu，
Your letter of 10 March to the British Council， Beijing， has been forwarded to me， and I am pleased to send you our Prospectus for the summer courses of 2005.（原因和目的）
…(ibid)
2.主体展开段
主体展开段的目的在于为整个文本的思想内容提供信息支撑。展开段是语篇文本最重要的段落主体，一篇文本可以没有引入段，没有过渡段，也可以没有结尾段，但是都存在展开段。因此，展开段的结构常常多种多样。因此，在本章节所讨论的除了引入段、过渡段和结尾段外，其他所有段落的结构都属于展开段落的结构。其展开可参照一般段落的基本要素：主题（包括明示的主题和蕴涵的主题），支撑主题的支撑句。展开段的标准：主题明确，语义逻辑清楚。主体展开段的具体展开情况参见本章节后面部分的讨论。
3.结尾段
结尾段的基本要素：主题的重点和结论。结尾段的标准：简明扼要。
主题重复在于使整个文本首尾照应，让文本给读者一个一气呵成，浑然一体的印象。
结尾段的展开常有以下一些结构模式：主题复述式、主题引申式、展望和期望式、尾首照应式等。
尾首照应式语例：
（1）"There are three kinds of lies-lies， damned lies， and statistics."Mark Twain.
Well， perhaps Mr.Twain didn't see the beauty of numbers the way that I do.Because ever since grade school， mathematics has been my favorite subject. And once I was in college and could focus on many areas of math， I realized that I had a genuine interest to applying mathematical and statistical theories to real-world concerns. Hey， even Twain the skeptic realized the importance of balancing the cargo on shallow， difficult-to-navigate riverboats so that the port and starboardsides were equally laden-he even advised the captains to part their hair down the middle so that the weight was perfectly distributed！
I am eager to start the work that will bring me my Ph.D.in statistics. I am also looking forward to continuing my investigation of how I can apply mathematical theories in the real world. Mark Twain may despair of my chosen career， but I agree with Thomas Carlyle， who said， Blessed is he who has found his work； let him ask no other blessedness.
（2）Little Lessons I've learned on my way..
In his poem， The Road Not Taken， Robert Frost wrote，"Two roads diverge in the woods， and I took the one least traveled by/ And that has made all the difference."In this poem， the narrator had a choice of two roads. However， I've discovered that life is a little more complicated. Sometimes the path we embark on is not always the one we choose. Sometimes we are pushed or pulled in certain directions and we have to react to our environment.
And as I offer myself as a Ph.D candidate in your Political Sociology department， I bring to the table years of work experience which includes steady and continuous promotions， an unrelenting pursuit for knowledge， a compassion for children and people， and a belief that anything is possible if we can actively imagine it into existence.Throughout my adult life， I never lost my path and I hope that you will allow me to continue this path at the University of Nebraska.
结尾段中的结论在于强化文章主要思想，给读者一个完结的交代。
4.过渡段
过渡段承担段落间的衔接、转承的角色任务。标准：自然，承上启下。
（二）根据文本功能和角色为标准，可以将文本段落分成引入段、展开段、结尾段、过渡段四种段落类型，它们各自都承担和履行了不同的文本功能和角色。而相比之下，对于一篇文本的语义思想的表达和阐释，文本的主体展开段落则无疑是起着最主要的作用。也就是说，文本的主体展开段主要承担文本的语义思想的表达和阐释的功能。所以，写好展开段落，对文本的思想内容表达具有十分重要的作用。
由于文本的主体展开段主要是服务于文本思想内容的表达的，所以，从这一角度来讲，文本的主体展开段又可称为文本的主题段。随着文本类型和文本的写作目的的不同，文本的主题段的展开可以采取多种多样的方式，如过程式、时序式、举例式、因果分析式等。
首先，根据英语段落的主要目的和基本的文体风格的不同，英语段落可以分为议论段落、描写段落、叙述段落和说明段落。这四种展开模式可以是单独的展开模式，也可以是组合式展开模式。
根据不同文本类型展开的段落，段落分为单一文本类型结构型、复合文本类型结构型。
单一文本类型。文本具有四种基本类型：议论文、说明文、描写文、记叙文。因此，段落也有议论型段落、说明型段落、描写型段落、记叙型段落。
复合文本类型结构段落，则是以一种文本类型为主，兼具其他文本展开方式为辅构成的段落。其中有议论-说明型、说明-议论型、描写-记叙型、记叙-描写型等。
（三）根据段落有无主题句，段落可以分为有主题句段落和无主题句段落。主题句是指用于表达一个段落的主要思想或指示段落主题方向或任务的句子。
有主题句段落。段落里主题句的特征是具有主题句。主题句的出现，理论上可以出现在段落中的任何位置（前面、中间、后面）。主题句放置的位置取决于写作者的思路、展开方法以及文本特点。理论上，有主题句段落和无主题句段落都可以出现在所有类型的文本当中，但相对而言，出于使语义表达更加简明的缘故常用于议论文，说明文则更多地采用有主题句段落。