string(284) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E7%9B%88%E4%BA%8F%E5%B9%B3%E8%A1%A1%E7%82%B9%E7%9A%84%E8%A1%A8%E7%A4%BA%E6%96%B9%E5%BC%8F%E6%9C%89%E5%93%AA%E4%BA%9B => Failed to connect to 101.91.112.32 port 38195: Connection refused"
盈亏平衡点的表示方式有哪些
