It's a joke, don't take it if you don't like it
The teacher asked a classmate: "Why did your homework book become like this?" The classmate said: "It fell into the water." The teacher said: "How did it fall into the water?" He lowered his head and said: "I accidentally fell into the water in the toilet..." Teacher: "It fell into the water in the toilet?" The classmate said: "It fell into the toilet." So the teacher cried up to the sky and screamed, then stretched out his index finger and said, "I turned the page page by page with saliva!"
