re
preposition uk/riː/ us/riː/
formal（尤用于商务信函中）关于，兹就，事涉
(especially in business letters) about; on the subject of
Re your communication of 15 February ... 兹就你2月15日来信…
（用于回复电子邮件时的标题行，在被回复的邮件的标题之前）
used in the subject line of an email when it is a reply to another email, followed by the subject of the original message
Re: invoice 回复：invoice