5. Passage Sixteen Justin was always prepared. His motto was “Never throw anything out， you never know when it might come in handy.” His bedroom was so full of flat bicycle tires， bent tennis rackets， deflated basketballs， and games with missing pieces that you could barely get in the door. His parents asked him to clean out his room. “What use is a fish tank with a hole in the bottom?” his father asked. But Justin simply smiled and repeated his motto， “Never throw anything out， you never know when it might come in handy.” When Justin was away from home， he always carried his blue backpack. He liked to think of it as a smaller version of his bedroom——a place to store the many objects that he collected. It was so worn and stretched that it hardly resembled a backpack anymore. It was full of the kind of things that seemed unimportant， but when used with a little imagination， might come in handy. Justin had earned a reputation for figuring things out and getting people out of otherwise hopeless situations. Many of his classmates and neighbors sought him out when they needed help with a problem. On the first day of school， his friend Kenny， came looking for Justin. “Do you think you have something in your bag that could help me remember my locker code?” he asked. “I lost the paper it was written on. I have science class in two minutes and if I’m late on the first day it’ll make me look bad for the rest of the year.” Kenny looked genuinely worried. “Relax，” Justin said， taking his backpack off and opened it. “Remember how you borrowed my notebook in hometown to write the code down? Well， I know how we can recover what you wrote. ” He took the notebook and a soft lead pencil out of his bag. The page that Kenny had written on had left faint indentations (旧凹痕) on another page in the notebook. Justin held the pencil on its side and rubbed it lightly over the indentations. Slowly but surely the numbers of the locker code appeared in white， set off by the gray pencil rubbings. “That’s amazing!” Kenny said. “I owe you one.” And he dashed off to open his locker. The author’s purpose in writing this story is to ( ) .