“To” and “From” replace a letter's inside address and signature block, for example.

比如，便笺上用“致”和“自”取代了信件内的地址和签名部分。

" To" and " From" replace a letter's inside address and signature block, for example. Further, letters are usually sent outside the organization, while memorandums are usually internal messages.

例如，“收件人”和“发件人”替换信件的内部地址和签名块。此外，信件通常发送到组织外部，而备忘录通常是内部消息。