第一种：
sudo vim /etc/resolv.conf
添加nameserver 8.8.8.8
第二种：
/etc/apt/sources.list 的内容换成
deb http://old-releases.ubuntu.com/ubuntu/ raring main universe restricted multiverse
deb-src http://old-releases.ubuntu.com/ubuntu/ raring main universe restricted multiverse
deb http://old-releases.ubuntu.com/ubuntu/ raring-security main universe restricted multiverse
deb-src http://old-releases.ubuntu.com/ubuntu/ raring-security main universe restricted multiverse
deb http://old-releases.ubuntu.com/ubuntu/ raring-updates main universe restricted multiverse
deb-src http://old-releases.ubuntu.com/ubuntu/ raring-updates main universe restricted multiverse
deb http://old-releases.ubuntu.com/ubuntu/ raring-backports main restricted universe multiverse
deb-src http://old-releases.ubuntu.com/ubuntu/ raring-backports main restricted universe multiverse
deb http://old-releases.ubuntu.com/ubuntu/ raring-proposed main restricted universe multiverse
deb-src http://old-releases.ubuntu.com/ubuntu/ raring-proposed main restricted universe multiverse
然后sudo apt-get update一下就行啦。。。。