我做了什么：
sudo apt-get remove python3
我得到的答复是：
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages were automatically installed and are no longer required:
bicyclerepair ca-certificates-mono cli-common dc extlinux gedit-common
gir1.2-appindicator3-0.1 gir1.2-gmenu-3.0 gir1.2-grilo-0.2 gir1.2-gudev-1.0
gir1.2-mediaart-2.0 gir1.2-rb-3.0 gir1.2-secret-1 gir1.2-tracker-1.0
gir1.2-udisks-2.0 guile-2.0-libs intel-gpu-tools kdesudo libandroid-properties1
libdbus-glib2.0-cil libdbus2.0-cil libgc1c2 libgconf2.0-cil libgdiplus
libgkeyfile1.0-cil libglib2.0-cil libgnome-keyring1.0-cil libgpod-common libgpod4
libgtk2.0-cil libhud2 libjs-sphinxdoc libjs-underscore libmessaging-menu0
libmono-accessibility4.0-cil libmono-addins0.2-cil libmono-cairo4.0-cil
libmono-corlib4.5-cil libmono-data-tds4.0-cil libmono-i18n-west4.0-cil
libmono-i18n4.0-cil libmono-ldap4.0-cil libmono-posix4.0-cil
libmono-security4.0-cil libmono-sharpzip4.84-cil libmono-sqlite4.0-cil
libmono-system-componentmodel-dataannotations4.0-cil
libmono-system-configuration4.0-cil libmono-system-core4.0-cil
libmono-system-data4.0-cil libmono-system-design4.0-cil
libmono-system-drawing4.0-cil libmono-system-enterpriseservices4.0-cil
libmono-system-ldap4.0-cil libmono-system-numerics4.0-cil
libmono-system-runtime-serialization-formatters-soap4.0-cil
libmono-system-runtime-serialization4.0-cil libmono-system-security4.0-cil
libmono-system-servicemodel-internals0.0-cil libmono-system-transactions4.0-cil
libmono-system-web-applicationservices4.0-cil libmono-system-web-services4.0-cil
libmono-system-web4.0-cil libmono-system-windows-forms4.0-cil
libmono-system-xml-linq4.0-cil libmono-system-xml4.0-cil libmono-system4.0-cil
libmono-webbrowser4.0-cil libnotify0.4-cil liboxideqt-qmlplugin liboxideqtcore0
liboxideqtquick0 libpeas-1.0-0-python3loader libpython3-dev libpython3.5-dev
libqt5feedback5 libqt5multimedia5 libqt5organizer5 libqt5positioning5
libqt5quicktest5 libqt5test5 librhythmbox-core9 libsgutils2-2 libubuntugestures5
libubuntutoolkit5 libunity-action-qt1 libunity-webapps0 libunwind8 libx86-1
mono-4.0-gac mono-gac mono-runtime mono-runtime-common mono-runtime-sgen mscompress
oxideqt-codecs plainbox-secure-policy pm-utils python-gconf python-kiwi python-vte
python3.5-dev qml-module-qt-labs-folderlistmodel qml-module-qt-labs-settings
qml-module-qtfeedback qml-module-qtgraphicaleffects qml-module-qttest
qml-module-ubuntu-components qml-module-ubuntu-layouts
qml-module-ubuntu-onlineaccounts qml-module-ubuntu-performancemetrics
qml-module-ubuntu-test qml-module-ubuntu-web qmlscene
qtdeclarative5-accounts-plugin qtdeclarative5-dev-tools
qtdeclarative5-qtquick2-plugin qtdeclarative5-test-plugin
qtdeclarative5-ubuntu-ui-toolkit-plugin qtdeclarative5-unity-action-plugin
rhythmbox-data suru-icon-theme syslinux syslinux-common syslinux-legacy tcl tk
ubuntu-mobile-icons ubuntu-ui-toolkit-theme unetbootin-translations
unity-webapps-qml unity-webapps-service vbetool vim-addon-manager webapp-container
webbrowser-app
Use 'sudo apt autoremove' to remove them.
The following additional packages will be installed:
kdesudo
The following packages will be REMOVED:
aisleriot apparmor apport apport-gtk aptdaemon apturl apturl-common atom bpython3
checkbox-converged checkbox-gui classicmenu-indicator command-not-found compiz
compiz-gnome dh-python docky firefox foomatic-db-compressed-ppds gconf-editor
gconf2 gdebi gdebi-core gdm3 gedit gir1.2-ibus-1.0 gksu gnome-menus gnome-music
gnome-orca gnome-shell gnome-terminal hplip hplip-data ibus ibus-table
idle-python3.5 idle3 language-selector-common language-selector-gnome
libbonoboui2-0 libgksu2-0 libgnome-2-0 libgnome2-0 libgnome2-bin libgnome2-common
libgnomeui-0 libgnomevfs2-0 libgnomevfs2-common libpurple-bin lsb-release
mysql-server mysql-server-5.7 nautilus-share onboard onboard-data openprinting-ppds
pida plainbox-provider-checkbox plainbox-provider-resource-generic
plymouth-theme-ubuntu-gnome-text plymouth-theme-ubuntu-text printer-driver-foo2zjs
printer-driver-foo2zjs-common printer-driver-postscript-hp printer-driver-ptouch
printer-driver-pxljr pyotherside python3 python3-apport python3-apt
python3-aptdaemon python3-aptdaemon.gtk3widgets python3-aptdaemon.pkcompat
python3-argcomplete python3-argh python3-blessings python3-blinker python3-brlapi
python3-bs4 python3-cairo python3-cffi-backend python3-chardet
python3-checkbox-support python3-commandnotfound python3-cryptography python3-cups
python3-cupshelpers python3-curtsies python3-dbus python3-debian python3-defer
python3-dev python3-distupgrade python3-feedparser python3-gdbm python3-gi
python3-gi-cairo python3-greenlet python3-guacamole python3-html5lib
python3-httplib2 python3-idna python3-jinja2 python3-jwt python3-louis python3-lxml
python3-mako python3-markupsafe python3-mysqldb python3-oauthlib python3-padme
python3-pathtools python3-pexpect python3-pil python3-pip python3-pkg-resources
python3-plainbox python3-problem-report python3-ptyprocess python3-pyasn1
python3-pyatspi python3-pycurl python3-pygments python3-pyparsing python3-renderpm
python3-reportlab python3-reportlab-accel python3-requests python3-setuptools
python3-six python3-software-properties python3-speechd python3-systemd python3-tk
python3-uno python3-update-manager python3-urllib3 python3-virtualenv
python3-watchdog python3-wcwidth python3-wheel python3-xdg python3-xkit
python3-xlsxwriter python3-yaml qml-module-io-thp-pyotherside rhythmbox
rhythmbox-plugin-zeitgeist rhythmbox-plugins sessioninstaller snapd
software-properties-common software-properties-gtk ssh-import-id
system-config-printer-common system-config-printer-gnome system-config-printer-udev
totem-plugins ubuntu-core-launcher ubuntu-desktop ubuntu-drivers-common
ubuntu-minimal ubuntu-release-upgrader-core ubuntu-release-upgrader-gtk
ubuntu-standard ubuntu-system-service ufw unattended-upgrades unetbootin unity
unity-control-center unity-control-center-signon unity-lens-photos
unity-scope-calculator unity-scope-chromiumbookmarks unity-scope-colourlovers
unity-scope-devhelp unity-scope-firefoxbookmarks unity-scope-gdrive
unity-scope-home unity-scope-manpages unity-scope-openclipart unity-scope-texdoc
unity-scope-tomboy unity-scope-virtualbox unity-scope-yelp unity-scope-zotero
unity-tweak-tool unity-webapps-common update-manager update-manager-core
update-notifier update-notifier-common usb-creator-common usb-creator-gtk vim-gnome
xdiagnose
The following NEW packages will be installed:
kdesudo
0 upgraded, 1 newly installed, 198 to remove and 3 not upgraded.
Need to get 26.1 kB of archives.
After this operation, 414 MB disk space will be freed.
Do you want to continue? [Y/n] y
Get:1 http://in.archive.ubuntu.com/ubuntu xenial/universe amd64 kdesudo amd64 3.4.2.4+repack-2ubuntu4 [26.1 kB]
Fetched 26.1 kB in 1s (13.3 kB/s)
(Reading database ... 422256 files and directories currently installed.)
Removing aisleriot (1:3.18.2-1ubuntu1) ...
Removing mysql-server (5.7.12-0ubuntu1.1) ...
Removing mysql-server-5.7 (5.7.12-0ubuntu1.1) ...
update-alternatives: using /etc/mysql/my.cnf.fallback to provide /etc/mysql/my.cnf (my.cnf) in auto mode
Removing snapd (2.0.9) ...
Warning: Stopping snapd.service, but it can still be activated by:
snapd.socket
Removing ubuntu-core-launcher (1.0.27.1) ...
Removing apparmor (2.10.95-0ubuntu2) ...
Removing apport-gtk (2.20.1-0ubuntu2.1) ...
Removing apport (2.20.1-0ubuntu2.1) ...
Removing ubuntu-desktop (1.361) ...
Removing language-selector-gnome (0.165.3) ...
Removing sessioninstaller (0.20+bzr150-0ubuntu4.1) ...
Removing aptdaemon (1.1.1+bzr982-0ubuntu14) ...
Removing nautilus-share (0.7.3-2ubuntu1) ...
Removing apturl (0.5.2ubuntu11.1) ...
Removing apturl-common (0.5.2ubuntu11.1) ...
Removing atom (1.8.0-1~webupd8~0) ...
Removing bpython3 (0.15-2) ...
Removing checkbox-gui (1.2.4-0ubuntu1) ...
Removing checkbox-converged (1.2.4-0ubuntu1) ...
Removing classicmenu-indicator (0.10.1-0ubuntu1) ...
Removing command-not-found (0.3ubuntu16.04.2) ...
Removing unity-tweak-tool (0.0.7ubuntu2) ...
Removing unity (7.4.0+16.04.20160526.1-0ubuntu1) ...
Removing gdm3 (3.18.3-0ubuntu2) ...
Please be sure to run "dpkg-reconfigure lightdm".
Removing compiz (1:0.9.12.2+16.04.20160526-0ubuntu1) ...
Removing compiz-gnome (1:0.9.12.2+16.04.20160526-0ubuntu1) ...
Removing gnome-shell (3.18.5-0ubuntu0.1) ...
Removing software-properties-gtk (0.96.20.2) ...
Removing software-properties-common (0.96.20.2) ...
Removing python3-software-properties (0.96.20.2) ...
Removing python3-uno (1:5.1.4-0ubuntu1) ...
Removing python3-pip (8.1.1-2ubuntu0.1) ...
Removing docky (2.2.1.1-1) ...
Removing firefox (47.0+build3-0ubuntu0.16.04.1) ...
Removing foomatic-db-compressed-ppds (20160212-0ubuntu1) ...
Removing gconf-editor (3.0.1-2ubuntu1) ...
Removing unetbootin (608-1) ...
Removing gdebi (0.9.5.7ubuntu1) ...
Removing gksu (2.0.2-9ubuntu1) ...
Removing libgksu2-0 (2.0.13~pre1-6ubuntu8) ...
Removing pida (0.5.1-6) ...
Removing vim-gnome (2:7.4.1689-3ubuntu1.1) ...
update-alternatives: using /usr/bin/vim.basic to provide /usr/bin/vi (vi) in auto mode
update-alternatives: using /usr/bin/vim.basic to provide /usr/bin/view (view) in auto mode
update-alternatives: using /usr/bin/vim.basic to provide /usr/bin/ex (ex) in auto mode
update-alternatives: using /bin/nano to provide /usr/bin/editor (editor) in auto mode
update-alternatives: using /usr/bin/vim.basic to provide /usr/bin/rvim (rvim) in auto mode
update-alternatives: using /usr/bin/vim.basic to provide /usr/bin/rview (rview) in auto mode
update-alternatives: using /usr/bin/vim.basic to provide /usr/bin/vimdiff (vimdiff) in auto mode
update-alternatives: using /usr/bin/vim.basic to provide /usr/bin/vim (vim) in auto mode
Removing libgnomeui-0:amd64 (2.24.5-3.1) ...
Removing gdebi-core (0.9.5.7ubuntu1) ...
Removing gedit (3.18.3-0ubuntu4) ...
Removing unity-control-center-signon (0.1.8+16.04.20160201-0ubuntu1) ...
Removing unity-control-center (15.04.0+16.04.20160413-0ubuntu3) ...
Removing ibus-table (1.9.1-3ubuntu2) ...
Removing ibus (1.5.11-1ubuntu2) ...
Removing gir1.2-ibus-1.0:amd64 (1.5.11-1ubuntu2) ...
Removing gnome-menus (3.13.3-6ubuntu3) ...
Removing gnome-music (3.18.2-1ubuntu1) ...
Removing gnome-orca (3.18.2-1ubuntu3) ...
Removing gnome-terminal (3.18.3-1ubuntu1) ...
update-alternatives: using /usr/bin/lxterm to provide /usr/bin/x-terminal-emulator (x-terminal-emulator) in auto mode
Removing printer-driver-postscript-hp (3.16.3+repack0-1) ...
Removing hplip (3.16.3+repack0-1) ...
Removing hplip-data (3.16.3+repack0-1) ...
dpkg: warning: while removing hplip-data, directory '/usr/share/hplip/fax' not empty so not removed
dpkg: warning: while removing hplip-data, directory '/usr/share/hplip/pcard' not empty so not removed
dpkg: warning: while removing hplip-data, directory '/usr/share/hplip/base/pexpect' not empty so not removed
dpkg: warning: while removing hplip-data, directory '/usr/share/hplip/installer' not empty so not removed
dpkg: warning: while removing hplip-data, directory '/usr/share/hplip/copier' not empty so not removed
dpkg: warning: while removing hplip-data, directory '/usr/share/hplip/scan' not empty so not removed
dpkg: warning: while removing hplip-data, directory '/usr/share/hplip/prnt' not empty so not removed
dpkg: warning: while removing hplip-data, directory '/usr/share/hplip/ui4' not empty so not removed
Removing idle3 (3.5.1-3) ...
Removing idle-python3.5 (3.5.1-10) ...
Removing ubuntu-standard (1.361) ...
Removing language-selector-common (0.165.3) ...
Removing libbonoboui2-0:amd64 (2.24.5-3ubuntu1) ...
Removing libgnome2-0:amd64 (2.32.1-5ubuntu1) ...
Removing libgnome2-bin (2.32.1-5ubuntu1) ...
Removing libgnome-2-0:amd64 (2.32.1-5ubuntu1) ...
Removing libgnome2-common (2.32.1-5ubuntu1) ...
Removing libpurple-bin (1:2.10.12-0ubuntu5) ...
Removing onboard-data (1.2.0-0ubuntu5) ...
Removing onboard (1.2.0-0ubuntu5) ...
Removing openprinting-ppds (20160212-0ubuntu1) ...
Removing plainbox-provider-checkbox (0.25-1) ...
Removing plainbox-provider-resource-generic (0.23-1) ...
Removing plymouth-theme-ubuntu-gnome-text (16.04.4) ...
update-alternatives: using /usr/share/plymouth/themes/ubuntu-text/ubuntu-text.plymouth to provide /usr/share/plymouth/themes/text.plymouth (text.plymouth) in auto mode
update-initramfs: deferring update (trigger activated)
Removing plymouth-theme-ubuntu-text (0.9.2-3ubuntu13.1) ...
update-initramfs: deferring update (trigger activated)
Removing printer-driver-foo2zjs (20151024dfsg0-1ubuntu1) ...
Removing printer-driver-foo2zjs-common (20151024dfsg0-1ubuntu1) ...
Removing printer-driver-ptouch (1.4-1) ...
Removing printer-driver-pxljr (1.4+repack0-4) ...
Removing pyotherside (1.4.0-2) ...
Removing xdiagnose (3.8.4) ...
Removing python3-apport (2.20.1-0ubuntu2.1) ...
Removing ubuntu-drivers-common (1:0.4.17.1) ...
Removing python3-commandnotfound (0.3ubuntu16.04.2) ...
Removing system-config-printer-gnome (1.5.7+20160212-0ubuntu2) ...
Removing python3-aptdaemon.pkcompat (1.1.1+bzr982-0ubuntu14) ...
Removing python3-aptdaemon.gtk3widgets (1.1.1+bzr982-0ubuntu14) ...
Removing python3-aptdaemon (1.1.1+bzr982-0ubuntu14) ...
Removing python3-argcomplete (0.8.1-1ubuntu2) ...
Removing python3-watchdog (0.8.3-2) ...
Removing python3-argh (0.26.1-1) ...
Removing python3-curtsies (0.2.6-1) ...
Removing python3-blessings (1.6-2build1) ...
Removing unity-lens-photos (1.0+14.04.20140318-0ubuntu1) ...
Removing python3-oauthlib (1.0.3-1) ...
Removing python3-blinker (1.3.dfsg2-1build1) ...
Removing python3-brlapi (5.3.1-2ubuntu2.1) ...
Removing python3-bs4 (4.4.1-1) ...
Removing python3-gi-cairo (3.20.0-0ubuntu1) ...
Removing python3-cairo (1.10.0+dfsg-5build1) ...
Removing python3-cryptography (1.2.3-1) ...
Removing python3-cffi-backend (1.5.2-1ubuntu1) ...
Removing ssh-import-id (5.5-0ubuntu1) ...
Removing python3-plainbox (0.25-1) ...
Removing usb-creator-gtk (0.3.2) ...
Removing usb-creator-common (0.3.2) ...
Removing python3-checkbox-support (0.22-1) ...
Removing system-config-printer-udev (1.5.7+20160212-0ubuntu2) ...
Removing system-config-printer-common (1.5.7+20160212-0ubuntu2) ...
Removing python3-cups (1.9.73-0ubuntu2) ...
Removing python3-cupshelpers (1.5.7+20160212-0ubuntu2) ...
Removing python3-defer (1.0.6-2build1) ...
Removing python3-dev (3.5.1-3) ...
Removing unity-scope-openclipart (0.1+13.10.20130723-0ubuntu1) ...
Removing python3-feedparser (5.1.3-3build1) ...
Removing python3-gdbm:amd64 (3.5.1-1) ...
Removing python3-pyatspi (2.18.0+dfsg-3) ...
Removing unity-webapps-common (2.4.17+15.10.20150616-0ubuntu2) ...
Removing python3-greenlet (0.4.9-2fakesync1) ...
Removing python3-guacamole (0.9.2-1) ...
Removing python3-html5lib (0.999-4) ...
Removing python3-httplib2 (0.9.1+dfsg-1) ...
Removing python3-idna (2.0-3) ...
Removing python3-jinja2 (2.8-1) ...
Removing python3-jwt (1.3.0-1) ...
Removing python3-louis (2.6.4-2) ...
Removing unity-scope-devhelp (0.1+14.04.20140328-0ubuntu1) ...
Removing python3-lxml (3.5.0-1build1) ...
Removing rhythmbox-plugins (3.3-1ubuntu7) ...
Removing python3-mako (1.0.3+ds1-1ubuntu1) ...
Removing python3-markupsafe (0.23-2build2) ...
Removing python3-mysqldb (1.3.7-1build2) ...
Removing python3-padme (1.1.1-2) ...
Removing python3-pathtools (0.1.2-2) ...
Removing python3-pexpect (4.0.1-1) ...
Removing python3-pil:amd64 (3.1.2-0ubuntu1) ...
Removing python3-setuptools (20.7.0-1) ...
Removing python3-virtualenv (15.0.1+ds-3) ...
Removing python3-problem-report (2.20.1-0ubuntu2.1) ...
Removing python3-ptyprocess (0.5-1) ...
Removing python3-pyasn1 (0.1.9-1) ...
Removing python3-pycurl (7.43.0-1ubuntu1) ...
Removing python3-pygments (2.1+dfsg-1) ...
Removing python3-pyparsing (2.0.3+dfsg1-1ubuntu0.1) ...
Removing python3-renderpm:amd64 (3.3.0-1) ...
Removing python3-reportlab (3.3.0-1) ...
Removing python3-reportlab-accel:amd64 (3.3.0-1) ...
Removing python3-speechd (0.8.3-1ubuntu3) ...
Removing python3-systemd (231-2build1) ...
Removing python3-tk (3.5.1-1) ...
Removing python3-wcwidth (0.1.6+dfsg1-1) ...
Removing python3-wheel (0.29.0-1) ...
Removing totem-plugins (3.18.1-1ubuntu4) ...
Removing python3-xdg (0.25-4) ...
Removing python3-xkit (0.5.0ubuntu2) ...
Removing python3-xlsxwriter (0.7.3-1) ...
Removing python3-yaml (3.11-3build1) ...
Removing qml-module-io-thp-pyotherside:amd64 (1.4.0-2) ...
Removing rhythmbox-plugin-zeitgeist (3.3-1ubuntu7) ...
Removing rhythmbox (3.3-1ubuntu7) ...
Removing ubuntu-minimal (1.361) ...
Removing ubuntu-system-service (0.3) ...
Removing ufw (0.35-0ubuntu2) ...
Skip stopping firewall: ufw (not enabled)
Removing unattended-upgrades (0.90) ...
Removing unity-scope-calculator (0.1+14.04.20140328-0ubuntu1) ...
Removing unity-scope-chromiumbookmarks (0.1+13.10.20130723-0ubuntu1) ...
Removing unity-scope-colourlovers (0.1+13.10.20130723-0ubuntu1) ...
Removing unity-scope-firefoxbookmarks (0.1+13.10.20130809.1-0ubuntu1) ...
Removing unity-scope-gdrive (0.9+16.04.20151125-0ubuntu1) ...
Removing unity-scope-home (6.8.2+16.04.20160212.1-0ubuntu1) ...
Removing unity-scope-manpages (3.0+14.04.20140324-0ubuntu1) ...
Removing unity-scope-texdoc (0.1+14.04.20140328-0ubuntu1) ...
Removing unity-scope-tomboy (0.1+13.10.20130723-0ubuntu1) ...
Removing unity-scope-virtualbox (0.1+13.10.20130723-0ubuntu1) ...
Removing unity-scope-yelp (0.1+13.10.20130723-0ubuntu1) ...
Removing unity-scope-zotero (0.1+13.10.20130723-0ubuntu1) ...
Removing libgnomevfs2-0:amd64 (1:2.24.4-6.1ubuntu1) ...
Removing libgnomevfs2-common (1:2.24.4-6.1ubuntu1) ...
Removing gconf2 (3.2.6-3ubuntu6) ...
Removing python3-requests (2.9.1-3) ...
Removing python3-urllib3 (1.13.1-2ubuntu0.16.04.1) ...
Removing dh-python (2.20151103ubuntu1.1) ...
Removing update-notifier (3.168) ...
Removing update-notifier-common (3.168) ...
Removing update-manager (1:16.04.3) ...
Removing ubuntu-release-upgrader-gtk (1:16.04.14) ...
Removing update-manager-core (1:16.04.3) ...
dpkg: warning: while removing update-manager-core, directory '/var/lib/update-manager' not empty so not removed
Removing ubuntu-release-upgrader-core (1:16.04.14) ...
Removing python3-distupgrade (1:16.04.14) ...
Removing python3-debian (0.1.27ubuntu2) ...
Removing python3-chardet (2.3.0-2) ...
Removing python3-dbus (1.2.0-3) ...
Removing python3-gi (3.20.0-0ubuntu1) ...
Removing python3-pkg-resources (20.7.0-1) ...
Removing python3-six (1.10.0-3) ...
Removing python3-update-manager (1:16.04.3) ...
Removing lsb-release (9.20160110ubuntu0.2) ...
Removing python3-apt (1.1.0~beta1build1) ...
Removing python3 (3.5.1-3) ...
Processing triggers for bamfdaemon (0.5.3~bzr0+16.04.20160523-0ubuntu1) ...
Rebuilding /usr/share/applications/bamf-2.index...
Processing triggers for desktop-file-utils (0.22-1ubuntu5) ...
Processing triggers for mime-support (3.59ubuntu1) ...
Processing triggers for libglib2.0-0:amd64 (2.48.1-1~ubuntu16.04.1) ...
Processing triggers for man-db (2.7.5-1) ...
Processing triggers for hicolor-icon-theme (0.15-0ubuntu1) ...
Processing triggers for shared-mime-info (1.5-2ubuntu0.1) ...
Unknown media type in type 'all/all'
Unknown media type in type 'all/allfiles'
Processing triggers for dbus (1.10.6-1ubuntu3) ...
Processing triggers for gnome-icon-theme (3.12.0-1ubuntu3) ...
Processing triggers for cups (2.1.3-4) ...
Processing triggers for menu (2.1.47ubuntu1) ...
Processing triggers for libc-bin (2.23-0ubuntu3) ...
Processing triggers for initramfs-tools (0.122ubuntu8.1) ...
update-initramfs: Generating /boot/initrd.img-4.4.0-28-generic
Processing triggers for doc-base (0.10.7) ...
Processing 3 removed doc-base files...
Registering documents with scrollkeeper...
Selecting previously unselected package kdesudo.
(Reading database ... 410312 files and directories currently installed.)
Preparing to unpack .../kdesudo_3.4.2.4+repack-2ubuntu4_amd64.deb ...
Unpacking kdesudo (3.4.2.4+repack-2ubuntu4) ...
Processing triggers for man-db (2.7.5-1) ...
Setting up kdesudo (3.4.2.4+repack-2ubuntu4) ...
update-alternatives: using /usr/bin/kdesudo to provide /usr/lib/kde4/libexec/kdesu (kdesu) in auto mode
为什么要删除 Firefox、Docky 等？
答案1
@StarOS 的回答（现已删除）是正确的，因为通过删除python3，您还删除了系统所需的许多关键依赖项以及许多其他软件包。
但是，他/她建议你使用 Boot-Repair 是错误的。相反，只需使用以下命令进入终端：
sudo apt-get install -f（-f-选项也写得--fix-broken更明确），以防您的系统出现某种故障。（请访问man apt-get以了解更多信息）。- 其次是
sudo apt-get install python3
正如@DavidFoerster 在下面的评论中所建议的：
$ sudo apt-get install -f ubuntu-minimal ubuntu-desktop
实际上会重建你的桌面，重新安装你丢失的软件包，其中包括python3。这将彻底修复你的安装。
答案2
在 Debian 测试中，对于 amd64 架构中的主要套件，至少有 365 个软件包直接依赖于 python3 软件包（根据 列出在 Depends 中ben query '.depends ~ "python3"' Packages_amd64 | grep -E 'Depends: .* python3 ' | wc -l），并且考虑到Canonical 计划将 Python 3 设为默认语言，因此有很多软件包依赖于它也就不足为奇了。这就是 python3 软件包如此重要的原因，但请注意它不会破坏您的系统……如果您安装了提取所有窗口/桌面管理器软件包的元软件包（即 ubuntu-desktop），您实际上可以从中恢复。
那么，为什么 apt 会因为你删除了 python3 而决定删除其他软件包呢？因为apt 有一个依赖解析器确保每次操作后，没有软件包具有未满足的依赖关系，并且当它找不到不会留下“损坏”依赖关系的解决方案时，它会拒绝删除它。APT 会警告您有关所有被删除的软件包，这些软件包列在“以下软件包将被删除“列表。您接受了它，然后它继续删除它们。