DEAR MISS MANNERS: I am a full-time college student. My university has scheduled all classes so that there is a 10-minute gap between each one, giving students time to get to their next class, use the restroom, grab a coffee, etc. This is generally respected by most of my professors, who let us out when class is supposed to be over. But I have one professor who repeatedly continues to lecture after class is supposed to be over, sometimes up to five minutes, which makes it difficult to get to my next class on time. I wouldn’t mind if this happened every once in a while for a minute or two, but …