deb http://mirrors.163.com/ubuntu/ precise main restricted universe multiverse deb http://mirrors.163.com/ubuntu/ precise-security main restricted universe multiverse deb http://mirrors.163.com/ubuntu/ precise-updates main restricted universe multiverse deb http://mirrors.163.com/ubuntu/ precise-proposed main restricted universe multiverse deb http://mirrors.163.com/ubuntu/ precise-backports main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ precise main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ precise-security main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ precise-updates main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ precise-proposed main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ precise-backports main restricted universe multiverse