Don't have Telegram yet? Try it now!
http://asc8384.top/2018/apt-get-%e6%8d%a2%e6%ba%90-ubuntu%e9%95%9c%e5%83%8f%e4%bd%bf%e7%94%a8%e5%b8%ae%e5%8a%a9.html
apt-get 换源——Ubuntu镜像使用帮助