string(263) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E4%BA%8C%E5%BB%BA%E6%A1%88%E4%BE%8B%E7%AD%94%E6%A1%88%E8%A6%81%E6%B1%82a-2%E5%86%99%E6%88%90a%3A2 => Failed to connect to 14.18.46.51 port 38206: Connection refused"
二建案例答案要求a-2写成a:2
