Daydreams (joke)

A teacher fell asleep during class one day.
After waking up, he said to his students, "I dreamt of Prince Zhou."
The next day, one of his students fell asleep in class.
The teacher woke him up with a whack of the wooden stick, saying, "How dare you fell asleep in class!"
The student said,"I dreamt of Prince Zhou, too."
"What did he say to you?"
"He said he didn't meet you yesterday."