NOT EVEN DOCTORS UNDERSTAND ‘RSVP’ DEAR MISS MANNERS: I am a retired physician from an academic medical center, and I continue to teach interested residents. I led a weekly seminar for senior residents last year. They worked very hard, and at the end of the year, my wife and I invited them to a reception at our home. The invitations included an RSVP. Very few responded, but they all showed up! I asked them why they had not responded, and the majority of these highly educated fifth-year residents — who have all completed college and four years of medical school — did not know the meaning of “…