—、书信写作要求
书信(Letter)一般可分为事务信件或公函(Business Letter or Offical Correspondence)以及私人信件
(Private Letter)两大类。一般包括以下几个要点：
1） 收信人的姓名和地址；
2） 寄信人的姓名及其与收信人的关系；
3） 寄信人的地址（有时可以省略）；
4） 写信的时间；
5） 信的内容。
1. 书信的格式
1） 信头(Heading)；
2） 称呼(Salutation)；
3） 正文(Body of the letter)；
4） 结束语(Complimentary close)；
5） 签名(signature)。
2. 书信的种类
1） 邀请信
邀请信有正式和非正式之分，也有介于两者之间者。正式邀请信一般属于公函类，私人邀请信一般属于非正式文体。邀请朋友、熟人参加某一聚会时，再词句上不一定多加斟酌，用词太正规倒显得关系不密切。但是如果与被邀请人不太熟悉的话，最好用正式文体。如虽认识但并不十分了解，文体可介于两个者之间。由此可见，私人邀请究竟用什么文体，关键看与被邀请人之间的亲疏的程度。邀请信要明确写出活动（是晚会、晚餐还是一般的聚会等）、活动的时间地点组织这项活动的理由，有时还应告诉对方可能出席的人，另外一般希望对方给予答复。
(1) 非正式邀请信，如；
26 Coventry St.
London
Sept. 15th, 1999.
Dear Jack,
I am going to the cinema to see the Red River Valley and I have two tickets. Would you like to come? The film starts at 7:30 p.m. Maybe we can meet at the Covent Garden Station at 7:00 p.m. and have a drink before the film starts. Please phone me at home to let me know.
Looking forward to seeing you.
Love
Mary
这封信是写给朋友的，所以用语比较随便，比较口语化。
(2) 正式邀请信，如：
Dear Ms. Gupta;
It’s our great pleasure to announce that Jan. 19th is the 3rd anniversary of the founding of our corporation. We have a small party as follows: 7:00p.m.,Jan. 19th, Room No.123, Kunlun Hotel. At this moment, we would like to express our sincere gratitude to our clients for both courtesy and support over the past three years. Please confirm if you plant to attend.
Yours Sincerely,
Lewis
这是一封正式邀请信，十分正规，无论从句式，还是用语都十分讲究。
(3) 介于正式和非正式之间的邀请信，如：
No.4 Middle School
Beijing 100034
April 29th,2000
Dear Miss Katherine,
I am very pleased to write to you. My name is Yu Hong and I am monitor of Class One, Grade Three of the No.2 Middle School of Ji'nan. Last year, you came here to give a speech, which was "Fast Reading". My classmates and I all thank you very much. We will have an English evening at 7:00--9:00 on the evening of May 4th in our classroom. Would you please come and attend the evening party? At the party, we will sing English songs, play games and so on. And we are anxious to invite you to come to sing us an English song. After that we can enjoy the music. We hope to see you soon.
Yours
Yu Hong
这封信是写给一位外籍教师的，这位外籍教师曾经到过这所学校，虽然作者认识，但并不十分了解。liuxuepaper.com