string(300) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E4%B8%80%E7%BA%A7%E5%BB%BA%E9%80%A0%E5%B8%882020%E7%89%88%E6%95%99%E6%9D%90%E5%92%8C2019%E7%89%88%E6%95%99%E6%9D%90%E5%8C%BA%E5%88%AB => Failed to connect to 14.18.117.71 port 38133: Connection refused"
一级建造师2020版教材和2019版教材区别
