"Back to School" joke

Summer vacation was over and Little Johnny returned back to school.
Only two days later his teacher phoned his mother to tell her that he was misbehaving.
"Wait a minute," she said. "I had Johnny with me for three months and I never called you once when he misbehaved!"
Physics Teacher: "Isaac Newton was sitting under a tree when an apple fell on his head and he discovered gravity. Isn`t that wonderful?"
Student: "Yes sir, if he had been sitting in class looking at books like us, he wouldn`t have discovered anything."
"If there are any idiots in the room, will they please stand up" said the sarcastic teacher.
After a long silence, one freshman rose to his feet.
"Now then mister, why do you consider yourself an idiot?" enquired the teacher with a sneer.
"Well, actually I don`t," said the student, "but I hate to see you standing up there all by yourself."
A little girl came home from school and said to her mother, "Mommy, today in school I was punished for something that I didn`t do."
The mother exclaimed, "But that`s terrible! I`m going to have a talk with your teacher about this. .. by the way, what was it that you didn`t do?"
The little girl replied, "My homework."