sudo cp /etc/apt/sources.list /etc/apt/source.list.bak 备份

文件内内容更改为如下

deb https://mirrors.ustc.edu.cn/ubuntu/ bionic main restricted universe multiverse

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

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

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

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

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

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

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

deb https://mirrors.ustc.edu.cn/ubuntu/ bionic-proposed main restricted universe multiverse

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

sudo apt-get update 更新

sudo apt-get -f install

sudo apt-get upgrade