Carbon paper allows two copies of a document to be made at once.

复写纸可让一份文件迅速印出两份复件。

Before email was popular and mechanical typewriters weren't just for hipsters, the quickest way to make copies of a document was to use a special sheet of paper called carbon paper.

在电子邮件普及之前，机械式打字机并不只是时尚人士的专利，复制文件最快的方法是使用一种叫做复写纸的特殊纸张。