Mary is a little girl.She is only five.She doesn't go to school.Of course(当然)she doesn't know how to read and write.But her brother,Tom,is a school-boy.He is ten.
One day Tom sees his sister at the door with a pen in her hand and a large piece of paper in front of her.
"What are you doing,Mary?"he says."I'm writing a letter to my friend Kitty",says Mary."But how can you?"says her brother."You do not know how to write".
"Well,"says Mary."It does not matter(没关系)because Kitty does not know how to read".