John is a famous writer now.But he said he was not a great student when he was young.He was often late for school and didn't like doing his homework.Sometimes,he slept in class while the teacher was teaching.He didn't understand much,although he always thought he understood everything.One day the teacher asked the students a question,"When Jack was ten years old,his brother Bob was twenty,Jack is fifteen now and how old is his brother Bob?" John said,"That's easy.Bob is twice as old as Jack,so he is now thirty." Another time,the teacher in a science class asked,"When it thunders,why do we always see the light before we hear the sound?"
"But Miss." said John quickly,"don't you know our eyes are in front of our ears?"