我使用debootstrap安装了ubuntu 20.04版本的基本系统，当我尝试安装软件包xfce4时得到了
root@localhost:~# apt install xfce4
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
xfce4 : Depends: thunar (>= 1.8.9) but it is not installable
Depends: xfce4-appfinder (>= 4.14.0) but it is not installable
Depends: xfce4-panel (>= 4.14.0) but it is not installable
Depends: xfce4-pulseaudio-plugin but it is not installable
Depends: xfce4-session (>= 4.14.0) but it is not installable
Depends: xfce4-settings (>= 4.14.0) but it is not installable
Depends: xfdesktop4 (>= 4.14.0) but it is not installable
Recommends: thunar-volman (>= 0.9.5) but it is not installable
Recommends: xfce4-notifyd but it is not installable
Recommends: xorg but it is not installable
E: Unable to correct problems, you have held broken packages.
当我尝试安装apt-add-repository时
root@localhost:~# apt install software-properties-common
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
software-properties-common : Depends: gir1.2-packagekitglib-1.0 (>= 1.1.0-2) but it is not installable
Depends: packagekit but it is not installable
E: Unable to correct problems, you have held broken packages.
这是我必须自己编写的souce.list文件的输出
root@localhost:~# cat /etc/apt/sources.list
deb http://archive.ubuntu.com/ubuntu/ focal universe
deb http://archive.ubuntu.com/ubuntu/ focal main
deb http://archive.ubuntu.com/ubuntu/ focal-updates main
deb http://archive.ubuntu.com/ubuntu/ focal-updates multiverse
deb http://archive.canonical.com/ubuntu focal partner
deb http://security.ubuntu.com/ubuntu/ focal-security main restricted
deb http://security.ubuntu.com/ubuntu/ focal-security universe
deb http://security.ubuntu.com/ubuntu/ focal-security multiverse
deb http://il.archive.ubuntu.com/ubuntu focal main
deb http://mirrors.kernel.org/ubuntu focal main
deb http://security.ubuntu.com/ubuntu/ focal universe
deb http://security.ubuntu.com/ubuntu/ focal multiverse
E
root@localhost:~# dpkg -i aptitude_0.8.10-6ubuntu1_i386.deb
Selecting previously unselected package aptitude.
(Reading database ... 25027 files and directories currently installed.)
Preparing to unpack .../aptitude_0.8.10-6ubuntu1_i386.deb ...
Unpacking aptitude (0.8.10-6ubuntu1) ...
dpkg: dependency problems prevent configuration of aptitude:
aptitude depends on aptitude-common (= 0.8.10-6ubuntu1); however:
Version of aptitude-common on system is 0.8.12-1ubuntu4.
aptitude depends on libapt-pkg5.0 (>= 1.1); however:
Package libapt-pkg5.0 is not installed.
aptitude depends on libboost-filesystem1.65.1; however:
Package libboost-filesystem1.65.1 is not installed.
aptitude depends on libboost-iostreams1.65.1; however:
Package libboost-iostreams1.65.1 is not installed.
aptitude depends on libboost-system1.65.1; however:
Package libboost-system1.65.1 is not installed.
aptitude depends on libcwidget3v5; however:
Package libcwidget3v5 is not installed.
aptitude depends on libncursesw5 (>= 6); however:
Package libncursesw5 is not installed.
aptitude depends on libsigc++-2.0-0v5 (>= 2.8.0); however:
Package libsigc++-2.0-0v5 is not installed.
aptitude depends on libtinfo5 (>= 6); however:
Package libtinfo5 is not installed.
aptitude depends on libxapian30; however:
Package libxapian30 is not installed.
dpkg: error processing package aptitude (--install):
dependency problems - leaving unconfigured
Errors were encountered while processing:
aptitude
root@localhost:~# apt-get install -f
Reading package lists... Done
Building dependency tree
Reading state information... Done
Correcting dependencies... Done
The following packages will be REMOVED:
aptitude
0 upgraded, 0 newly installed, 1 to remove and 0 not upgraded.
1 not fully installed or removed.
After this operation, 4519 kB disk space will be freed.
Do you want to continue? [Y/n]