It'll be cheaper than sending it using their overnight service and we can still track it.

这比使用他们的通宵服务寄送更便宜，而且我们仍然可以跟踪它。

Sometimes that's called " express service." Both private companies such as UPS and FedEX, as well as the public mail service in the United States, the U.S. Postal Service, all of them offer overnight service.

有时这被称为“快递服务” 。 无论是UPS和FedEX这样的私人公司，还是美国的公共邮件服务， 美国邮政服务， 它们都提供隔夜服务。