我目前正在尝试按照这些说明在 Ubuntu 18.04 上安装 .NET Core。但我总是收到以下消息：
me@mine-Ubuntu:~$ sudo apt-get install -y dotnet-sdk-2.1.200
[sudo] password for me:
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:
dotnet-sdk-2.1.200 : Depends: dotnet-runtime-2.0.7 but it is not going to be installed
E: Unable to correct problems, you have held broken packages.
我发现了一些关于这个问题的帖子，但没有帮助。我希望在这里得到一些适当的信息。