Let's not get so literal-minded here. You are still allowed to say you are sitting in a theater seat, for example, even while you go to the concession stand during intermission. It's an allowed sense of the verb form; just as when someone asks "where are you working now?", the right answer (if you are really trying to communicate and not be a smartass) is not "I'm not working, am !? I'm standing here talking to you, aren't I?...you jerk!" . There are lots of ordinary constructions that use this verb construction, which I am sure has some kind of fancy name, to include a larger framework of time than the immediate moment -- "where are you studying", or for that matter, "Meet Jim -- he's studying astrophysics" when the guy is OBVIOUSLY standing right there with a beer in his hand.A