考研书信要求写信的主体，包括4个方面的内容：称呼（salutation），正文（body），礼貌性结尾（complimentary close，相当于汉语的此致敬礼），签名（name of the sender：寄信人）。
称呼一般就是Dear…。Dear后面怎么写，取决于收信人是谁？取决于写信人和收信人之间的关系。写信人对收信人如何称呼，亲密的人之间叫得亲密一点，不亲密的人之间叫得不亲密一点。考研书信是正式信函，分两种情况：一是题目没有告诉你收信人是谁？比如你在火车站大厅，买了一个Mp3，回去不能听，请求退款，或者换一个，那么写信的对象是对方经理，这种不知道对方姓名的情况用Dear Sir or Madam，后面跟逗号冒号都可以，一般用逗号。第二种情况是知道对方的名字，写成Dear＋姓，如2005年对象是王先生，所以写成Mr. Wang，注意活用Miss，Mr，Mrs和Ms就行了。
I am writing to thank…for…/express my gratitude for…
I am writing to ask for…
I am writing to apply for…
看一下2005年考研英语大纲样题：
Directions：
You are preparing for an English test and are in need of some reference books. Write a letter to the sales department of a bookstore to ask for：
1） detailed information about the books you want，
2） methods of payment，
3） time and way of delivery.
You should write about 100 words on Answer Sheet 2. Do not sign your own name at the end of the letter. UseLi Minginstead. You do not need to write the address.
以这道题为例，第一段新东方考研英语教材里面写成：
I am writing for information about test preparation materials for the IELTS test.
还可以写成：
I am writing to ask for information about test preparation materials for the TOEFL test.或者
I am writing to inquire about simulated BEC test papers available at your store.等等。
再比如2005年的辞职信，第一段可以写成：
I am writing to inform you of my decision to resign from my present position as an editor.
或者
I am writing to inform you that I have decided to resign from my present position as an editor.
正文第二段，100个字左右，8、9句话。
此段写作的中心任务是把题目中的提纲进行扩展。如果有3条提纲，可以每一条提纲扩充3句。怎么样扩充，主要是发挥点小小的想象力，有两种思路，一是将上义拆分成为若干下义，二是把一件事情说得更为形象具体。比如第一条指令，题目里面说是books，可以细化为各种各样的书，这就是下义拆分法。还可以具体描写一下这些书是什么样子的。同样第二个指令里面的methods of payment，和第三个指令里面的time and way of delivery都可以采用这两种方法进行扩展。
看2005年书信真题：
Directions：
Two months ago you got a job as an editor for the magazine Design＆Fashion. But now you find that the work is not what you expected. You decide to quit. Write a letter to your boss,Mr. Wang,telling him your decision,stating your reasons and making an apology.
Write your letter with no less than 100 words. Write it neatly on Answer Sheet 2. Do not sign your own name at the end of the letter,useLi Minginstead. You do not need to write the address.
Three reasons have persuaded me into such a decision. To be frank,I feel rather disoriented at my job because to be a journalist interviewing celebrities has long been my dream. I simply cannot sit still at the office!Though you promised me at my recruitment you would transfer me to the Interview Department in one month,yet two months has passed and there seems no sign of any change. Besides,the wage you offer me is so surprising low for my devotion to the Magazine that I am now even considering from whom to lend money to pay for my rent!Last but not the least,I am not interested in the office politics here,and most of the time,I feel quite out of place.
礼貌性的套话，一般都是焦急等待着您的回信I am looking forward to your reply足以，或者I would appreciate it if you could send a replay at your earliest convenience也行。
正文的语言大纲要求注意语域，其实就是使用正式体，这在选词时要注意，比如不要用缩写，不用口语词，比如：Please inform me if it''s OK.要改成Please inform me if it is ready等。
