deb http://mirrors.ustc.edu.cn/ubuntu/ bionic main multiverse restricted universe
deb http://mirrors.ustc.edu.cn/ubuntu/ bionic-backports main multiverse restricted universe
deb http://mirrors.ustc.edu.cn/ubuntu/ bionic-proposed main multiverse restricted universe
deb http://mirrors.ustc.edu.cn/ubuntu/ bionic-security main multiverse restricted universe
deb http://mirrors.ustc.edu.cn/ubuntu/ bionic-updates main multiverse restricted universe
deb-src http://mirrors.ustc.edu.cn/ubuntu/ bionic main multiverse restricted universe
deb-src http://mirrors.ustc.edu.cn/ubuntu/ bionic-backports main multiverse restricted universe
deb-src http://mirrors.ustc.edu.cn/ubuntu/ bionic-proposed main multiverse restricted universe
deb-src http://mirrors.ustc.edu.cn/ubuntu/ bionic-security main multiverse restricted universe
deb-src http://mirrors.ustc.edu.cn/ubuntu/ bionic-updates main multiverse restricted universe