Ubuntu中使用apt/apt-get 时报错：Unable to fetch some archives, maybe run apt-get update or try with --fix-m

在Ubuntu系统环境下，如果出现在进行 apt update或者apt install时，出现Unable to fetch some archives, maybe run apt-get update or try with --fix-missing问题，解决办法可以如下：

bash:
cat /etc/apt/sources.list
可以看到报错的源：Failed to fetch http://archive.ubuntu.com/ubuntu/

修改：
cp /etc/apt/sources.list /etc/apt/sources.list .bak
vim /etc/apt/sources.list
替换为：
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-security main restricted universe multiverse