書信是日常生活中常用的文體，是用以交涉事宜、傳達信息、交流思想、聯絡感情、增進了解的重要工具。書信一般可分為商務信件或公函（Business Letter or Official Correspondence）和私人信件（Private Letter）兩大類。值得注意的是，英語書信的寫法與漢語書信有一些明顯區別，應特別加以區分。
英語書信通常包括下面幾個組成部分：信端、信內地址、稱呼、正文、結束語、簽名、附件、再啟等。下面我們將逐個進行介紹。
1.信端（Heading）
信端即信頭，一般包括寫信人的地址和寫信日期。一些正式信函的信端還包括發信人或單位的電話號碼、電報掛號、電傳、傳真和郵政編碼等。
西方國家中有些信端甚至還有單位負責人的姓名、職務和職稱等。
信端的目的是使收信人一看便知道書信來自何處，何時發出，便于復信和查閱。用一般的信紙寫信時，信端應寫在信紙的右上角，若字數較多，可從信紙中間或偏右的地方寫起。若字數較少，可適當多向右移一些，使整個信端的重心落在右上角。
信端的寫法主要有并列式和斜列式兩種。從目前情況來看，前者更為常用。
采用并列式時，每行開頭要左對齊；采用斜列式時，每行開頭逐次向右移二三個字母的`距離。
例如
（1）并列式
16 Fuxing Street
Haidian District
Beijing
Post Code: 100035
People’s Republic of China
Tel: 63211234
Aug. 20, 2004
（2）斜列式（Indented Form）
16 Fuxing Street
Haidian District
Beijing
Post Code: 100035
People’s Republic of China
Tel: 63211234
Aug. 20, 2004
寫信端時，先寫發信人的地址，地點的名稱按由小到大的順序排列，然后與其它項目和發信日期。具體次序是：第一行寫門牌號和街名；第二行寫區名、市（縣）名、省（州、邦）名，往國外寄的信，還要寫上國家的名稱；國家名稱的前面加上郵政編碼，其后可寫上電話號碼，最后一行寫發信日期。如果寫信人的地址是機關單位的名稱，則將其作為第一行。如果寫信人的單位沒有門牌號碼和街名，則第一行可寫上所在班級或專業組的名稱；第二行寫系、科、室名稱；第三行寫學校名稱；第四行寫市（縣）、省（州）名稱；然后再寫郵政編碼、國名、電話號碼、發信日期等項。
如果使用標點符號，則在每行末尾加逗號，最后一行的末尾加句號。但當前的信件中行末大都不加標點符號，但在每行之內該用標點符號的地方，仍要用標點。
特別要注意的是，門牌號碼和街名之間要加逗號。月份和日期之間不可用逗號。在西方國家，城市名稱之后往往寫有字母或數字（如 New York, 103），表示城市的郵政編碼。
Writing a Paragraph： Focus on Coherence and Unity
The last chapter discussed the importance of using good grammar and good word choice in your writing. However, the most grammatically perfect paragraph will not receive a good grade if it is poorly organized and not focused on a central idea. The paragraph must have unity and coherence. These ideas were discussed briefly in chapter 22, but in this chapter we will explore unity and coherence more fully so that you can learn how these elements impact your writing.
As you learned in Chapter 22, coherence is whether or not what you write makes sense and whether or not the ideas are arranged in a logical manner. If ideas are out of order in writing, then the reader has a very difficult time trying to understand your point. As a result the reader will lose interest and you will not be able to convey your point.
Unity is equally important. Unity means that your writing sticks to one point at a time. When you mix and match ideas in writing jumping from one idea to the next and back again, the reader has a hard time following you. Inevitably, the reader will not understand your point and will eventually lose interest. This chapter explores ways to help you make certain that your writing is both coherent and unified.
Writing a Paragraph： Devising a Plan -- Outline
Once you have generated a topic sentence and the details to support that topic sentence, it is time to organize your ideas. By organizing your ideas you will create a clear picture of the structure of your paragraph. The most efficient way to organize ideas is to outline them. With the aid of an outline you will be able to decide if you have enough supporting ideas for your topic sentence and you will be able to eliminate those details that do not support your topic sentence. The outline will also let you test various methods of organization to decide which one suits your topic sentence the best and let you test the placement of your topic sentence within the paragraph to see where it will have the greatest impact on the reader. With the use of an outline you should be able to create organized, coherent, unified, well-supported paragraphs.
Writing a Paragraph： Polishing, Proofreading, and Preparing Final Copy？Final Lines
The last step in the writing process is proofreading. After you have finished developing and supporting your ideas and after you have checked the organization, it is time to put the finishing touches on your paragraph. As your last step you need to check the spelling, punctuation, mechanics, and word choice of your paragraph as well as check to be certain you have a concluding statement. You cannot check all of these things in one reading so you should break the task into sections. First, check the punctuation and mechanics of your paragraphs. This means you are making sure you don't have errors like comma splices or fragments. You are also making sure you put question marks at the ends of questions and periods at the ends of statements.
The next step is to check your word choice and spelling. You want to be sure that you have used the correct words for your intended meaning, so you want to be sure that you haven't used a two when you need a too. Be sure to double check the spelling of any word you often misspell and look up any word you are unsure of. If you are word processing, use the spell check on your computer to help you with your possible spelling mistakes.
Writing from Reading
The first step when you write from what you read is to be sure you understand what you have read. To ensure your understanding, you should be an active reader. This means that you should read more than once with a different purpose each time, you should ask questions before, during, and after you read, and you should make notes as you read.
Once you have read actively, you will be prepared to write in a number of different ways. You will be able to summarize what you have read. That means you are accurately re-telling the author's main ideas in your own words. A summary also gives the major supporting details the author has used to support the main ideas. Once again though, summaries are written in YOUR words not the author's words.
Another method of writing about what you have read is to respond to the reading. When you respond to a reading, you pick out a particular point or idea that the author has made and then brainstorm to develop your own ideas based on the author's thought. Unlike summarizing, you are generating your own ideas based on the author's original thought.
Rather than generating a new idea, you may also choose to respond to an idea in the reading. You may agree or disagree with a point the author has made. In your writing, you will explain why you agree or disagree with that point. Once again, you are coming up with your own reasoning and your own wording in response to something you have read.
A particular type of writing you will be required to do is writing answers to essay tests. Essay test questions often ask you to read material and then either summarize the material or respond to it in a particular way. The one thing that makes essay test writing different from other writing situations is the time limit. In a testing situation you will carefully monitor your use of time and you won't put all of the polishing touches in that you would if you had unlimited time to complete the writing.
These are some of the ways you can tie the material that you read to the material you write. You will find that if you follow the advice given in this chapter that you will never be at a loss for a topic to write about.
Writing a Paragraph： Focus on Support and Details
In this chapter you will study the importance of being specific in the details you use to support an idea. When you write in vague, general terms, you leave the reader to interpret what you mean and often the reader will not have enough information to accurately do that. You must be clear in your meaning so that anyone who reads your work understands exactly what you want him to understand.
It is equally important that you provide enough information to support your ideas. Generally you need 3 to 5 examples per idea to be sure you've given sufficient support. The best way to develop support is to ask yourself questions about your ideas. You can evaluate the support at each stage of the writing process. Much of the work that you do in the rough lines editing is evaluating support and asking questions to be sure you have said enough to clearly communicate your ideas to your audience.
Once you have gathered together as many details as you think you need, you then organize them with a rough outline. This gives you another opportunity to check for sufficient support. Does each section of the outline seem developed? Is there more than one detail for each section? Have you used specific rather than general words as you've outlined? At this point you double-check the topic sentence to be sure it covers all your details. Always remember that the more details you put in the outline the more details will make it into your paragraph.
If you are at a loss for details, try turning to your senses. Asking questions about how something looks, feels, tastes, smells, and sounds can provide you with plenty of details. When you are describing an event ask questions like who, what, when, where, how, and why. Read the lecture below for further information on developing support and details for your writing.