My mail slot has a lot of intra-office and inter-office letters and memos.

我的信箱里有很多办公室内的和办公室之间的信件和备忘录。

youdao

If I want to send something to someone who works for my company - my bank, but in another office, perhaps in the other side of the city, then I put it in inter-office mail.

如果我想送一些东西给和我在同一家公司工作的人—在我所工作的银行，但在另一个办公室，也许在城市的另一边，然后我把它放进办公室间的邮件箱。

youdao

This way, at the end of the day someone will carry a large bag with all the inter-office mail to the other office, because this is cheaper and usually much faster than using the regular public mail.

这样，在一天结束时，有人会带着一个大袋子，里面装着所有办公室间的邮件去往另一个办公室，因为这比使用普通的公共邮件更便宜，通常快得多。

youdao

Inter-office mail is code 37, intra-office mail 37-3, outside mail is 3-37.

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