书信包括：感谢、道歉、建议、求职/离职、申请、投诉、倡议、询问、慰问、推荐等。
1、格式
称呼：位于作文第一行，顶格写，后面加逗号。
不知道对方姓名、职位等信息时称呼可以用 Dear Sir or Madam, 或To Whom It May Concern； 知道对方的身份
或姓名时，称呼可以用Dear Mr./Mrs. + 姓， 或Dear+ 职位,如：Dear Professor, Dear Mr. Smith, ; 如果是给熟悉
的人则可以用Dear + 名， 如：Dear Jim/Betty.
正文：可采用齐头式，即每一段每一行都顶格写。或者采用缩进式，即每段首行缩进四个字母。
结束语：位于正文右下角，第一个单词的首字母要大写，后面要加逗号。常用结束语有：
Yours,/Yours truly, / Yours sincerely, 等
署名：位于结束语下方。考研作文不允许署真名，题目中一般要求签名为“Li Ming”或”Zhang Wei”

2、篇章结构
第一段：表明身份，写信目的（1-2句）。
第二段：针对题目中的要求进行写作（描述事情的经过、缘由、以及提出的建议）（3-4句）。
第三段：表示感谢、期待回信或表达希望。（1-2句）

范文一：
Dear President,
Being a senior student in this university, I am writing this letter with the hope of improving the students’ physical condition, as a growing number of students are getting much fatter, according to the latest survey.

Here are some suggestions I would like to put forward. First of all , greater attention should be attached to the physical condition of college students, and I hope you could play a vital role in spreading such an idea. Mean while, more sport apparatus and sport fields may be needed, as more students have enrolled in this great university year by year.

I do hope you can take the above suggestions into consideration and thanks in advance.

Yours sincerely,
Li Ming

范文二：
Dear Mr. Smith,
On behalf of the Student Union, I am sending this e-mail to you to invite you to act as our judge of English speech contest to be held in our university on June 5.

To be more specific, our contest is on the topic of how to embrace tough challenges in this digital era. During this competition, ten participants will deliver their speeches with respect to this topic. It is widely acknowledged that you are a top expert in this field, so we sincerely hope that you can accept our invitation. For further information, please call me at 9999999.

We are looking forward to your reply and arrival.

Yours truly,
Zhang Wei