我已经尝试过sudo apt-get install g++，但我遇到了以下错误：
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: g++: Depends: g++-7
(>= 7.2.0-1~) but it is not going to be installed E: Unable to correct
problems, you have held broken packages.
我应该如何解决这个问题？
尝试以下命令：