开头: do not hesitate to make a request if it is reasonable
要求:make the request specific ,using a polite tone
convincingly the reason for the request
let the recipient know why you came to him/her for help
mention it if there is something in return
问题补充: do not hesitate to make a request if it is reasonable 这个也是要求!!!谢谢!!不是开头!!!不是生日。。。。