单词拼写：
1. I have good reading ___________(理解), so I can understand it.
2. You should give clear ______________(说明) for all the exercises.
3. By the time the police arrived, the thief had ____________(消失).
4. In the United States, many _____________(青少年) begin to smoke.
5. Our English teacher likes ______________ (文学) very much.
