Ubuntu 20.04系统默认官方源/腾讯云源/中科大源/清华源source.list

老王用国外服务器和腾讯云服务器较多，所以优先列一下这两者。

1. 默认官方源source.list

deb http://archive.ubuntu.com/ubuntu/ focal main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ focal main restricted universe multiverse

deb http://archive.ubuntu.com/ubuntu/ focal-security main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ focal-security main restricted universe multiverse

deb http://archive.ubuntu.com/ubuntu/ focal-updates main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ focal-updates main restricted universe multiverse

deb http://archive.ubuntu.com/ubuntu/ focal-backports main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ focal-backports main restricted universe multiverse

## Not recommended
# deb http://archive.ubuntu.com/ubuntu/ focal-proposed main restricted universe multiverse
# deb-src http://archive.ubuntu.com/ubuntu/ focal-proposed main restricted universe multiverse

2. 腾讯云内网source.list

deb http://mirrors.tencentyun.com/ubuntu/ focal main restricted universe multiverse
deb-src http://mirrors.tencentyun.com/ubuntu/ focal main restricted universe multiverse

deb http://mirrors.tencentyun.com/ubuntu/ focal-security main restricted universe multiverse
deb-src http://mirrors.tencentyun.com/ubuntu/ focal-security main restricted universe multiverse

deb http://mirrors.tencentyun.com/ubuntu/ focal-updates main restricted universe multiverse
deb-src http://mirrors.tencentyun.com/ubuntu/ focal-updates main restricted universe multiverse

deb http://mirrors.tencentyun.com/ubuntu/ focal-backports main restricted universe multiverse
deb-src http://mirrors.tencentyun.com/ubuntu/ focal-backports main restricted universe multiverse

## Not recommended
# deb http://mirrors.tencentyun.com/ubuntu/ focal-proposed main restricted universe multiverse
# deb-src http://mirrors.tencentyun.com/ubuntu/ focal-proposed main restricted universe multiverse

3. 中科大源source.list

deb https://mirrors.ustc.edu.cn/ubuntu/ focal main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ focal main restricted universe multiverse

deb https://mirrors.ustc.edu.cn/ubuntu/ focal-security main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ focal-security main restricted universe multiverse

deb https://mirrors.ustc.edu.cn/ubuntu/ focal-updates main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ focal-updates main restricted universe multiverse

deb https://mirrors.ustc.edu.cn/ubuntu/ focal-backports main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ focal-backports main restricted universe multiverse

## Not recommended
# deb https://mirrors.ustc.edu.cn/ubuntu/ focal-proposed main restricted universe multiverse
# deb-src https://mirrors.ustc.edu.cn/ubuntu/ focal-proposed main restricted universe multiverse

4. 清华源source.list

deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal main restricted universe multiverse
deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal main restricted universe multiverse

deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-security main restricted universe multiverse
deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-security main restricted universe multiverse

deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-updates main restricted universe multiverse
deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-updates main restricted universe multiverse

deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-backports main restricted universe multiverse
deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-backports main restricted universe multiverse

## Not recommended
# deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-proposed main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-proposed main restricted universe multiverse

5. 腾讯云source.list

deb https://mirrors.cloud.tencent.com/ubuntu/ focal main restricted universe multiverse
deb-src https://mirrors.cloud.tencent.com/ubuntu/ focal main restricted universe multiverse

deb https://mirrors.cloud.tencent.com/ubuntu/ focal-security main restricted universe multiverse
deb-src https://mirrors.cloud.tencent.com/ubuntu/ focal-security main restricted universe multiverse

deb https://mirrors.cloud.tencent.com/ubuntu/ focal-updates main restricted universe multiverse
deb-src https://mirrors.cloud.tencent.com/ubuntu/ focal-updates main restricted universe multiverse

deb https://mirrors.cloud.tencent.com/ubuntu/ focal-backports main restricted universe multiverse
deb-src https://mirrors.cloud.tencent.com/ubuntu/ focal-backports main restricted universe multiverse

## Not recommended
# deb https://mirrors.cloud.tencent.com/ubuntu/ focal-proposed main restricted universe multiverse
# deb-src https://mirrors.cloud.tencent.com/ubuntu/ focal-proposed main restricted universe multiverse