They had a mail service, although it was for official use only.

建立了邮政系统，虽然只供官方使用。

耶鲁公开课 - 新约课程节选

I should have also mentioned another really important information technology that developed in the nineteenth century was the Postal Service, although we had mail before then.

我应该也提到过,另一个产生于19世纪的,非常重要的信息技术,就是邮政服务，虽然我们在此之前就有信件往来。

耶鲁公开课 - 金融市场课程节选