—That's terrible. Even some streets were full of water.

   When I was 16 years old, a boy gave me an important gift. It was a smile.
   It was the early autumn of my first year at a junior high school, and my old school was far away. As a result, no one knew who I was. I was very lonely, and afraid to make friends with anyone.
   Every time I heard the other students talking and laughing, I felt my heart break. I couldn’t talk about anyone with my problems. And I didn’t want my parents to worry about me.
   Then one day, my classmates talked happily with their friends, but I sat at my desk unhappily as usual. At that moment, a boy came into the classroom. I didn’t know who he was. He passed me and then turned back. He looked at me, without a word, only a smile.
Suddenly, I felt the touch of something bright and friendly. It made me feel happy, lively and warm.
   That smile changed my life. I started to talk with other students and made friends. Day by day, I became closer to everyone in my class. The boy with the lucky smile has become my best friend now.
   One day I asked him why he smiled, but he couldn’t remember smiling at me!It doesn’t matter because all the dark days have gone. I believe that the world is what you think it is. If you think it lonely, you might always be alone. So smile at the world and it will smile back.

关于声现象的说法正确的是（  ）