阅读下面短文，在空格处填入一个适当的词或使用括号中所给词语的正确形式填空。
Sixteen years ago, a boy gave meimportant gift. It was a smile.
It was the early autumn of my(one) year at middle school, and my old school was far away. As a result, no one knew who I was. I was very lonely, and afraid to speak to anyone.
Every time I heard the other students talking and(laugh), I felt my heart break. I couldn't talk with anyone about my problems.
Then one day, when my classmates were talking(happy) with their friends, I was sitting at my desk unhappily as usual. At that moment, a boy entered the classroom. I didn't know who he was. He passed by me and then(turn) back. He looked at me a smile.
Suddenly, I felt the touch of something bright and friendly. It made me feel happy and warm. That smile changed my life. I started to talk with other students and made (friend). Day by day, I became(close) to everyone in my class. The boy with the smile has become my best friend now. One day, I asked himhe had smiled, but he couldn't remember doing so!
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 is lonely, you might always be alone. So smile at the world it will smile back.