string(337) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E5%A4%8D%E6%95%B0%E7%9A%84%E4%B9%98%E9%99%A4%E8%BF%90%E7%AE%97%E5%8F%8A%E5%85%B6%E5%87%A0%E4%BD%95%E6%84%8F%E4%B9%89%E8%A7%86%E9%A2%91%E8%AE%B2%E8%A7%A3%E6%95%99%E5%AD%A6 => Failed to connect to 14.18.117.71 port 38093: Connection refused"
复数的乘除运算及其几何意义视频讲解教学
