string(305) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=2021%E4%BA%8C%E5%BB%BA%E6%95%99%E6%9D%90%E4%B8%80%E8%88%AC%E6%98%AF%E6%AF%8F%E5%B9%B4%E4%BB%80%E4%B9%88%E6%97%B6%E5%80%99%E5%87%BA%E7%9A%84 => Failed to connect to 14.18.117.71 port 38093: Connection refused"
2021二建教材一般是每年什么时候出的
