RSVP stands for the French phrase répondez s’il vous plaît (“reply, please”) so it doesn’t need an added “please.” However, since few people seem to know its literal meaning, and fewer still take it seriously, it’s best to use plain English” “Please reply.” And for those of you receiving such an invitation, yes, you have to let the host know whether you are coming or not, and no, you can’t bring along the kids or other uninvited guests.
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