string(278) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E4%BA%8C%E5%BB%BA21%E5%B9%B4%E6%95%99%E6%9D%90%E5%92%8C20%E5%B9%B4%E6%95%99%E6%9D%90%E5%93%AA%E4%B8%AA%E5%A5%BD => Failed to connect to 14.18.117.71 port 38069: Connection refused"
二建21年教材和20年教材哪个好
