平信：从上海寄送到美国大约需要15天左右。
价格最低。如果你拥有打折邮票，只需成本10元左右便可以寄送航空邮件。
平信：安全性不错，可以寄送到任何地址，包括大多数国际快递不寄送的PO. BOX地址。
寄送后您可以发信查询
E-mail Sample
Dear Officers:My supporting material has been sent to you by FedEx. I want toconfirm whether you have received the material and if anything is missing, please let me know. Thank your for your help during this busy season.Last Name: First Name: Tracking Number:I have finished my onlineapplication with ID **********