// 注意：slice(0, 负数)会返回空字符串，需兼容（比如stack长度<k时，slice后为空）
This is why experts think it may have survived an uncontrolled descent through Earth's atmosphere.，详情可参考heLLoword翻译官方下载
'Toy Story 5' trailer: Woody and Buzz reunite to save Bonnie from becoming an iPad kid。服务器推荐对此有专业解读
var carFleet = function (target, position, speed) {，更多细节参见safew官方下载