string(256) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E9%9B%AA%E7%9A%84%E5%BD%A2%E6%88%90%E5%B1%9E%E4%BA%8E%E4%BB%80%E4%B9%88%E7%8E%B0%E8%B1%A1 => Failed to connect to 14.18.117.71 port 38069: Connection refused"
雪的形成属于什么现象
