我尝试在 Ubuntu 18.04 上安装 clang，但无法安装。我尝试sudo apt install clang并得到了这些结果：
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:
clang : Depends: clang-6.0 (>= …