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