Ubuntu解决Failed to fetch https://... Could not resolve ‘某个源‘

在我使用sudo apt install subversion的时候遇到报错：

这个报错与Ubuntu操作系统的软件源配置文件有关系。错误提示显示无法解析“mirrors.shanhe.com”地址，这可能是由于更新软件包列表或下载软件包时出现的网络问题。

1.可以先更新一下源试试：

sudo apt-get update

如果不能解决，就换一个源，这个没关系的，方法如下：

sudo nano /etc/apt/sources.list

然后将https://mirrors.shanhe.com/ubuntu源替换，我这里替换的是清华的：https://mirrors.tuna.tsinghua.edu.cn/ubuntu

还有其他可用：

https://mirrors.aliyun.com/ubuntu：阿里云镜像站点
https://mirrors.tuna.tsinghua.edu.cn/ubuntu：清华大学TUNA镜像站点
https://mirrors.ustc.edu.cn/ubuntu：中国科学技术大学镜像站点

# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu focal main restricted
# deb-src https://mirrors.shanhe.com/ubuntu focal main restricted

## Major bug fix updates produced after the final release of the
## distribution.
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu focal-updates main restricted
# deb-src https://mirrors.shanhe.com/ubuntu focal-updates main restricted

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please note that software in universe WILL NOT receive any
## review or updates from the Ubuntu security team.
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu focal universe
# deb-src https://mirrors.shanhe.com/ubuntu focal universe
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu focal-updates universe
# deb-src https://mirrors.shanhe.com/ubuntu focal-updates universe

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team, and may not be under a free licence. Please satisfy yourself as to
## your rights to use the software. Also, please note that software in
## multiverse WILL NOT receive any review or updates from the Ubuntu
## security team.
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu focal multiverse
# deb-src https://mirrors.shanhe.com/ubuntu focal multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu focal-updates multiverse
# deb-src https://mirrors.shanhe.com/ubuntu focal-updates multiverse

## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu focal-backports main restricted universe multiverse
# deb-src https://mirrors.shanhe.com/ubuntu focal-backports main restricted universe multiverse

## Uncomment the following two lines to add software from Canonical's
## 'partner' repository.
## This software is not part of Ubuntu, but is offered by Canonical and the
## respective vendors as a service to Ubuntu users.
# deb http://archive.canonical.com/ubuntu focal partner
# deb-src http://archive.canonical.com/ubuntu focal partner

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

更改结束后如果直接安装东西还是会出现👇