Yep, Miella knows: Basically, they do a lot of combining classes, so the missing teacher's class is in the same room as a teacher who is there - or getting other teachers to cover classes on their free periods and lunch breaks - or taking co-teachers and aides out of special-ed classrooms to cover other classes - or sending administrators in as subs. (This happens both in bad economic times - when they can't afford to pay subs - and in good economic times - when nobody's willing to sub for what they pay them.)

This sucks for everyone involved, from the students who have to put up with it, to the administrators who have to coordinate it! But that's our American school system, that is.