string(276) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E4%B8%AD%E7%BA%A7%E6%95%99%E6%9D%90%E4%B9%B0%E5%93%AA%E4%B8%AA%E7%89%88%E6%9C%AC%E6%AF%94%E8%BE%83%E5%A5%BD => Failed to connect to 101.89.117.144 port 38076: Connection refused"
中级教材买哪个版本比较好
