apt修改为阿里源， sudo vim /etc/apt/sources.list之后出现问题:

W: 无法下载 http://mirrors.aliyun.com/ubuntu/dists/jammy/InRelease  暂时不能解析域名“mirrors.aliyun.com”
W: 无法下载 http://mirrors.aliyun.com/ubuntu/dists/jammy-security/InRelease  暂时不能解析域名“mirrors.aliyun.com”
W: 无法下载 http://mirrors.aliyun.com/ubuntu/dists/jammy-updates/InRelease  暂时不能解析域名“mirrors.aliyun.com”
W: 无法下载 http://mirrors.aliyun.com/ubuntu/dists/jammy-proposed/InRelease  暂时不能解析域名“mirrors.aliyun.com”
W: 无法下载 http://mirrors.aliyun.com/ubuntu/dists/jammy-backports/InRelease  暂时不能解析域名“mirrors.aliyun.com”
W: 无法下载 https://ppa.launchpadcontent.net/deadsnakes/ppa/ubuntu/dists/jammy/InRelease  暂时不能解析域名“ppa.launchpadcontent.net”
W: 部分索引文件下载失败。如果忽略它们，那将转而使用旧的索引文件。

原因

DNS没有配置好

解决

sudo  vim /etc/resolv.conf
# 或
sudo vim /run/systemd/resolve/stub-resolv.conf # 建议改这个

添加nameserver,如下：(使用阿里巴巴提供的DNS域名解析服务)

# 添加
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
#     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN

nameserver 223.5.5.5
nameserver 223.6.6.6