What we don't get here is a sense of whether there really is an alternate secret postal system that serves a sort of underground of private networks.

在这里我们所不明白的是，是否真的存在一个,提供地下的,私密的通信服务的，秘密邮政系统。

耶鲁公开课 - 1945年后的美国小说课程节选

But, they did it through the postal system.

但他们通过邮政系统取得了成功。

耶鲁公开课 - 金融市场课程节选

Now, the really fascinating thing is that we have the same system today, except we don't use the postal service as the conduit anymore.

最妙的是,我们现在有同样的制度，除了我们不再将邮政服务作为纽带。

耶鲁公开课 - 金融市场课程节选