PV操作

PV操作简单理解   http://blog.csdn.net/liushuijinger/article/details/7586656

pv原语的定义及解释理解  http://blog.csdn.net/sinat_27042305/article/details/51590476

苹果桔子问题1 http://wenku.baidu.com/link?url=DFPvFw4bkDMttX68VWz6nn7J94OzWOBwf4e0hUKKg-65ik3G7HyjRx72LeJeuMNQXw5WMf0PMeosMrnwWyVRT4TPUhCJxHQ2Mo6dNNHy5cq

苹果桔子问题2 http://wenku.baidu.com/link?url=2fXECc8kD7loEKnczz64LbmupIgN3Qbcj2QDbtWX1Fqx9U0WpGMpoxedMlgDApej1b_LTKMEEyGpA9okEKT6IAlde_vUIWEpm3xnhrH0Z7O

http://www.cnblogs.com/cocowool/archive/2012/06/11/2544823.html