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