string(276) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E6%9C%89%E8%B6%A3%E7%9A%84%E7%89%A9%E7%90%86%E7%8E%B0%E8%B1%A1%E5%B9%B6%E6%8F%90%E5%87%BA%E9%97%AE%E9%A2%98 => Failed to connect to 125.88.227.171 port 38114: Connection refused"
有趣的物理现象并提出问题
