The romance between Claire and Eric is seemingly beautiful. Sure, she might be a bit older than he is, but in the trailer for “A Teacher,” the beginning moments show that both are madly in love with each other and are incredibly happy. There’s just the problem that Claire is a high school teacher and Eric is her, uh, student. And therein lies the awfulness of the relationship and why “A Teacher” is going to be a must-see series when it debuts in November.