// 易错点4：栈空时要存-1（题目要求无更大值返回-1），而非直接存stack2.at(-1)（会得到undefined）
The company is also planning to go public this year, according to numerous reports.，更多细节参见旺商聊官方下载
（四）购进农产品时，除取得增值税专用发票或者海关进口增值税专用缴款书外，按照农产品收购发票或者农产品销售发票计算的进项税额，国务院另有规定的除外；，推荐阅读WPS官方版本下载获取更多信息
But questions remain about how realistic the goal and timeframe are, given recent and steep Nasa budget cuts, and some scientists are concerned that the plans are driven by geopolitical goals.