string(310) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E4%BA%8C%E5%BB%BA%E8%8A%B1%E9%92%B1%E4%B9%B0%E7%9A%84%E8%AF%BE%E7%A8%8B%E5%92%8C%E5%85%8D%E8%B4%B9%E7%9A%84%E6%9C%89%E5%8C%BA%E5%88%AB%E5%90%97 => Failed to connect to 14.18.117.71 port 38093: Connection refused"
二建花钱买的课程和免费的有区别吗
