What happen to my son

　　我的儿子怎么了

　　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, It's 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，父亲带着儿子来到了一颗树下。他测量了儿子的身高，并用钉子做了记号。他希望儿子明年还会长得更高。冬天，大雪皑皑。但是，那颗树上的钉子还在那里。春天来了，小树长高了。父亲又带儿子来到了这颗树下。他很想看一看儿子到底长了多高。让他惊讶的是，他发现儿子的身高低于树上的标识。他想不通这到底发生了什么呢?