一、服务器更新时，改成使用阿里云的源，安装software-properties-common出现依赖问题

二、方法一：一直往下安装，发现依赖有问题

三、方法二：查看可能包依赖不满足，How do I resolve The following packages have unmet dependencies

sudo apt-get update
sudo apt-get clean
sudo apt-get autoremove

sudo apt --fix-broken install
sudo apt-get update && sudo apt-get upgrade
sudo dpkg --configure -a
sudo apt-get install -f

四、方法四：修改使用官方源更新

• 看到一篇文章安装python3-tk出现依赖问题，说改用阿里云源的官方源可以解决
• 改成16.04阿里云官方源，更新后还是出现问题，这时候本来就怀疑源有问题，就改用官方源，重新更新就可以用，如果改用18.04阿里云官方源也可以解决问题
• sudo vim /etc/apt/sources.list
• sudo apt-get update

# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://cn.archive.ubuntu.com/ubuntu/ bionic main restricted
# deb-src http://cn.archive.ubuntu.com/ubuntu/ bionic main restricted

## Major bug fix updates produced after the final release of the
## distribution.
deb http://cn.archive.ubuntu.com/ubuntu/ bionic-updates main restricted
# deb-src http://cn.archive.ubuntu.com/ubuntu/ bionic-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 http://cn.archive.ubuntu.com/ubuntu/ bionic universe
# deb-src http://cn.archive.ubuntu.com/ubuntu/ bionic universe
deb http://cn.archive.ubuntu.com/ubuntu/ bionic-updates universe
# deb-src http://cn.archive.ubuntu.com/ubuntu/ bionic-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 http://cn.archive.ubuntu.com/ubuntu/ bionic multiverse
# deb-src http://cn.archive.ubuntu.com/ubuntu/ bionic multiverse
deb http://cn.archive.ubuntu.com/ubuntu/ bionic-updates multiverse
# deb-src http://cn.archive.ubuntu.com/ubuntu/ bionic-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 http://cn.archive.ubuntu.com/ubuntu/ bionic-backports main restricted universe multiverse
# deb-src http://cn.archive.ubuntu.com/ubuntu/ bionic-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 bionic partner
# deb-src http://archive.canonical.com/ubuntu bionic partner

deb http://security.ubuntu.com/ubuntu bionic-security main restricted
# deb-src http://security.ubuntu.com/ubuntu bionic-security main restricted
deb http://security.ubuntu.com/ubuntu bionic-security universe
# deb-src http://security.ubuntu.com/ubuntu bionic-security universe
deb http://security.ubuntu.com/ubuntu bionic-security multiverse
# deb-src http://security.ubuntu.com/ubuntu bionic-security multiverse