Unmet dependencies in installing virtualbox-5.2

[慕 冬亮 <mudongliangabcd@hotmail.com>]

Hi all,

my host system is Debian Buster(i.e., Debian Testing). When I installed 
Virtualbox-5.2, I encountered "unmet dependencies". The details is in 
the following:

$ sudo apt install virtualbox-5.2
[sudo] password for mdl:
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:
  virtualbox-5.2 : Depends: libcurl3 (>= 7.16.2) but it is not going to 
be installed
                   Depends: libvpx4 (>= 1.6.0) but it is not installable
                   Recommends: libsdl-ttf2.0-0 but it is not going to be 
installed
                   Recommends: linux-image but it is not installable
E: Unable to correct problems, you have held broken packages.

What should I do to fix broken packages?

-- Best Regards

Dongliang Mu