deb http://mirrors.tencent.com/debian-archive/debian buster main contrib non-free
deb-src http://mirrors.tencent.com/debian-archive/debian buster main contrib non-free
deb http://mirrors.tencent.com/debian-archive/debian-security buster/updates main contrib non-free
deb-src http://mirrors.tencent.com/debian-archive/debian-security buster/updates main contrib non-free
deb http://mirrors.tencent.com/debian-archive/debian buster-updates main contrib non-free
deb-src http://mirrors.tencent.com/debian-archive/debian buster-updates main contrib non-free
deb http://mirrors.ustc.edu.cn/debian/ buster-backports main contrib non-free
deb-src http://mirrors.ustc.edu.cn/debian/ buster-backports main contrib non-free