string(248) "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%95%99%E6%9D%90%E7%AC%AC%E5%9B%9B%E7%89%88%E8%AF%BE%E5%90%8E%E7%AD%94%E6%A1%88 => Received HTTP code 403 from proxy after CONNECT"
二建教材第四版课后答案
