He shows the class a film adaptation of Romeo and Juliet at the beginning of New Moon. In the movie, he asks Edward to recite Romeo's last lines to show he was paying attention (he was talking to Bella at the time). He looks on disturbed when Edward recites the words perfectly, and asks his students to return their glances to the screen to watch the last parts of the movie.
Bella and Edward walk into his class right as he was reciting a Frost poem. When he noticed their 'secret' exchange, he approaches them and asks Edward if there is something he would like to share. He then scans Edward's notes - transcription of his lecture - before walking away frowning.