sources.list

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