为什么B是-40m，C是-28m

为什么B是-40m，C是-28m

- -题目。。

When I was a child, I was fascinated by the melody of piano on the screen. At that time, I dreamed of being a pianist and having my own piano.　　At the age of five, my father bought me a beautiful piano as my birthday present with the money they had saved for a long time. At the same time, my father found a piano teacher for me and every day I would practise it again and again as my father demanded. Before long, my interest in piano was transferred to other things.　　I began to escape the practice as much as I could. My father found out my impatience. He encouraged me and was stricter with me than ever before. With his help, I underwent the hardest time and devoted myself to the piano.　　Now, in my spare time after a long time of study and hard work, I always play the piano and enjoy the beautiful music

你说细滴啊！