阅读理解，根据短文的意思，选择最合适的答案。    
     It's 7:30 on Monday morning. It's time for Tom to go to school. Classes begin at 7:40. But Tom is still in his room. His mother says, "Tom, it's late. You must be quick." "Mum, where is my pencil box? I can't find it. I can't go to school." Tom asks his mother.

    Look at Tom's room. What a mess(乱七八糟)! His books are on the floor. His shoes are on the desk. A kite and some clothes are in his bed. Tom's mother comes to help him. She put the books away and says,"Look, your pencil box is under the books. You must take good care of your things."