string(254) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=2020%E5%B9%B4%E4%B8%AD%E7%BA%A7%E6%95%99%E6%9D%90%E5%92%8C2019%E5%B9%B4%E5%8C%BA%E5%88%AB => Failed to connect to 14.18.46.51 port 38206: Connection refused"
2020年中级教材和2019年区别
