Etiquette rules followed in most Western cultures require that if you receive a formal, written invitation, you should reply promptly, perhaps that same day.

西方文化的礼仪要求，若您收到一份正式的书面邀请，那就应该立刻回复——最好是在同一天里。

youdao

Sandy's mother told her, "When you get an invitation, you should reply as soon as possible."

桑迪的妈妈通知桑迪：倘若你收到了请柬，你要尽快答复。

youdao

You should reply to let the person who sent the invitation know whether or not you plan to go.

你应该回复，让发出邀请的人知道你是否打算去。

youdao

" And in such case, "you should destroy this message and kindly notify the sender by reply email.

WSJ: Email Disclaimers Proliferate

You know, major manufacturers should just start handing out class action lawsuit form letters and business reply mail envelopes with their various electronics, just to make these things easier for everyone involved.

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