string(261) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=2020%E4%BA%8C%E5%BB%BA%E6%9C%BA%E7%94%B5%E6%95%99%E6%9D%90%E5%8F%98%E5%8C%96%E5%AF%B9%E6%AF%94 => Failed to connect to 101.89.120.29 port 38058: Connection refused"
2020二建机电教材变化对比
