普通邮件

例句：

1. 1. I need to send a regular mail to my friend in Beijing.
   我需要寄一封常规邮件给我在北京的朋友。
2. 2. The post office has stopped delivering regular mail due to the pandemic.
   由于疫情，邮局已经停止递送常规邮件了。
3. 3. She received a regular mail from her sister last week.
   她上周收到了来自姐姐的常规邮件。