He had only one pupil.
He chicken tendered his resignation.
He got crped out.
Pupil: At night. Teacher: Why did you say that Pupil: Because my Dad always says that Rome wasn't built in a day!
Pupil: You told me to put it in the Net.
A droid
Grandma and grandpa.
Because he only had one pupil! The joke is that I have no friends