Here is a video that explains better

来源: 于 2011-09-07 19:02:38 [博客] [旧帖] [给我悄悄话] 本文已被阅读：次

http://blog.wenxuecity.com/blogview.php?date=201109&postID=3712.html

 

I haven't finished watching it yet. Very... long.