直接放链接, 希望已经沉迷的人都好好看看这2个链接的东西
https://www.zhihu.com/question/24037357/answer/26711963
http://baike.baidu.com/link?url=qQ4NhpWP8D6z0qd_25duk6QTXq25oCUfVdFe_G5kAVxTE3jMqKME5Fke3e5gczEI1tcvPhslWqbhnq0mCyK25a
https://www.zhihu.com/question/24037357/answer/26711963
http://baike.baidu.com/link?url=qQ4NhpWP8D6z0qd_25duk6QTXq25oCUfVdFe_G5kAVxTE3jMqKME5Fke3e5gczEI1tcvPhslWqbhnq0mCyK25a