Official Chinese source debhttp: // response
Official Chinese source
Deb http://mirror.lupaworld.com/Ubuntu feisty main restricted universe multiverse
Deb http://mirror.lupaworld.com/ubuntu feisty-security main restricted universe multiverse
Deb http://mirror.lupaworld.com/ubuntu feisty-updates main restricted universe multiverse
Deb http://mirror.lupaworld.com/ubuntu feisty-backports main restricted universe multiverse
The deb-src http://mirror.lupaworld.com/ubuntu feisty main restricted universe multiverse
Deb-src http://mirror.lupaworld.com/ubuntu feisty-security main restricted universe multiverse
Deb-src http://mirror.lupaworld.com/ubuntu feisty-updates main restricted universe multiverse
Deb-src http://mirror.lupaworld.com/ubuntu feisty-backports main restricted universe multiverse cn99.com source deb http://ubuntu.cn99.com/ubuntu/ feisty main restricted universe multiverse
Deb http://ubuntu.cn99.com/ubuntu/ feisty-security main restricted universe multiverse
Deb http://ubuntu.cn99.com/ubuntu/ feisty-updates main restricted universe multiverse
Deb http://ubuntu.cn99.com/ubuntu/ feisty-proposed main restricted universe multiverse
Deb http://ubuntu.cn99.com/ubuntu/ feisty-backports main restricted universe multiverse
The deb-src http://ubuntu.cn99.com/ubuntu/ feisty main restricted universe multiverse
Deb-src http://ubuntu.cn99.com/ubuntu/ feisty-security main restricted universe multiverse
Deb-src http://ubuntu.cn99.com/ubuntu/ feisty-updates main restricted universe multiverse
Deb-src http://ubuntu.cn99.com/ubuntu/ feisty-proposed main restricted universe multiverse
Deb-src http://ubuntu.cn99.com/ubuntu/ feisty-backports main restricted universe multiverse then sudo apt-get update
Sudo apt-get dist-upgrade