Ubuntu 18.04 LTS下，要安装Virtual Box，我们需要先从Virtual Box官网下载相应的.deb安装包：

https://download.virtualbox.org/virtualbox/5.2.16/virtualbox-5.2_5.2.16-123759~Ubuntu~bionic_amd64.deb

当前最新版本为5.2.16，如果有新版本，请在以下链接查看下载相应版本：

https://www.virtualbox.org/wiki/Linux_Downloads

但是双击安装时，我们发现安装不上。我们用命令行安装一下：

eagle@EagleEye:~/Downloads$ sudo dpkg -i virtualbox.deb

Selecting previously unselected package virtualbox-5.2.
(Reading database ... 187180 files and directories currently installed.)
Preparing to unpack virtualbox-5.2_5.2.16-123759_Ubuntu_bionic_amd64.deb ...
Unpacking virtualbox-5.2 (5.2.16-123759~Ubuntu~bionic) ...
dpkg: dependency problems prevent configuration of virtualbox-5.2:
 virtualbox-5.2 depends on libqt5opengl5 (>= 5.0.2); however:
  Package libqt5opengl5 is not installed.
 virtualbox-5.2 depends on libqt5printsupport5 (>= 5.0.2); however:
  Package libqt5printsupport5 is not installed.
 virtualbox-5.2 depends on libqt5x11extras5 (>= 5.6.0); however:
  Package libqt5x11extras5 is not installed.
 virtualbox-5.2 depends on libsdl1.2debian (>= 1.2.11); however:
  Package libsdl1.2debian is not installed.

dpkg: error processing package virtualbox-5.2 (--install):
 dependency problems - leaving unconfigured
Processing triggers for ureadahead (0.100.0-20) ...
Processing triggers for systemd (237-3ubuntu10.3) ...
Processing triggers for gnome-menus (3.13.3-11ubuntu1) ...
Processing triggers for desktop-file-utils (0.23-1ubuntu3.18.04.1) ...
Processing triggers for mime-support (3.60ubuntu1) ...
Processing triggers for hicolor-icon-theme (0.17-2) ...
Processing triggers for shared-mime-info (1.9-2) ...
Errors were encountered while processing:
 virtualbox-5.2

可以看到，原来是有dependencies没有安装。
手动安装一下：

eagle@EagleEye:~/Downloads$ sudo apt-get install libqt5opengl5 libqt5printsupport5 libqt5x11extras5 libsdl1.2debian

完成之后，再安装一次Virtual Box：

eagle@EagleEye:~/Downloads$ sudo dpkg -i virtualbox.deb

(Reading database ... 188033 files and directories currently installed.)
Preparing to unpack virtualbox-5.2_5.2.16-123759_Ubuntu_bionic_amd64.deb ...
Unpacking virtualbox-5.2 (5.2.16-123759~Ubuntu~bionic) over (5.2.16-123759~Ubuntu~bionic) ...
Setting up virtualbox-5.2 (5.2.16-123759~Ubuntu~bionic) ...
addgroup: The group `vboxusers' already exists as a system group. Exiting.
Processing triggers for ureadahead (0.100.0-20) ...
Processing triggers for systemd (237-3ubuntu10.3) ...
Processing triggers for gnome-menus (3.13.3-11ubuntu1) ...
Processing triggers for desktop-file-utils (0.23-1ubuntu3.18.04.1) ...
Processing triggers for mime-support (3.60ubuntu1) ...
Processing triggers for hicolor-icon-theme (0.17-2) ...
Processing triggers for shared-mime-info (1.9-2) ...

这样Virtual Box的安装就完成了！