* 获取数字的第digit位（从右往左，0表示个位）
Finch said she "woke up screaming" after the surgery.
'Defensive attitude'，推荐阅读服务器推荐获取更多信息
When a SpaceX rocket failure set the skies aflame over western Europe last February, no-one was sure if the debris was also polluting our atmosphere.，更多细节参见快连下载安装
Managing Side Effects: A JavaScript Effect System in 30 Lines or Less
so that it is easy to reuse the (big) array instead of consuming it，更多细节参见旺商聊官方下载