Send a text message to the teacher without replying.

Maybe the teacher is too busy to answer. Maybe the teacher lent his mobile phone to someone else. You just sent a short message, and someone turned it on and off. Another thing is that the teacher left his mobile phone somewhere. In a word, it is definitely not that the teacher doesn't like you if he doesn't answer. Don't worry. If you are really not worried, just learn something ... (extra points ...)