在美式英语中，对于普通的邮件，通常的、最广为被使用的做法是：在Dear （人名）的后面使用逗号（即：comma）。但是，如果是相当正式（formal）的邮件（信函），其做法则是在Dear XXX后面使用冒号（即：colon）。
英文书信怎么写
一，英语作文书信格式：
1，最上面顶格写你要把信写给谁。
2,第二段写你要对这个朋友要说的话。
3，写完后最后的一行写上你自己的名字。
二，范文：
Dear Mike,
I am glad to introduce my family to you. My family is a warm and happy family. My grandparents are both teachers, they are still teaching in a university.Grandpa is for maths, and Grandma is for English, sometimes their students cometo our home to send their greetings to them. My father is working in an American factory,he is very busy. Every evening he is doing his work in the midnight. At weekend he alwaysgoes to factory for his work. My mother is a nurse. Her hospital is near my home. I am a student in Junior high school. I hope you will introduce your family to me
yours
sincerely
Tom