上限了.
http://image.baidu.com/i?ct=201326592&cl=2&lm=-1&nc=1&ie=utf-8&tn=baiduimage&pv=&fm=rs2&word=%E9%BB%91%E5%8C%96%E7%90%89%E6%98%9F%E7%9A%84%E9%AB%98%E6%B8%85%E5%9B%BE%E7%89%87
