## 替换成 阿里镜像源
vi /etc/apt/sources.list
deb http://mirrors.aliyun.com/ubuntu focal main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu focal-updates main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu focal-backports main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu focal-security main restricted universe multiverse
sudo apt update