What happen to my son

　　我的兒子怎么了

　　In autumn, a father took his son to a small tree. He measured his son and knocked in a nail as a mark. He hoped the boy could go taller in the next year. In winter, Its snowed very hard. However, the nail was still intrunk of tree all the time. Spring came, and the small tree grew stronger. Father brought his son to the treeagain. He was eager to see how much the boy had gone since last year. To his surprise, he found that his son was shorter than the mark. He wondered what happened to my son?

　　某年秋天，父親帶著兒子來到了一顆樹下。他測量了兒子的身高，并用釘子做了記號。他希望兒子明年還會長得更高。冬天，大雪皚皚。但是，那顆樹上的釘子還在那里。春天來了，小樹長高了。父親又帶兒子來到了這顆樹下。他很想看一看兒子到底長了多高。讓他驚訝的是，他發現兒子的身高低于樹上的標識。他想不通這到底發生了什么呢?