我使用apt-get运行了此命令，但收到此错误。我不太确定该如何解决。这是我使用apt-get犯的核心错误，要求做一些不可能的事情吗？有谁知道阻止其安装的根本原因？
sudo apt-get install openjdk-8-jdk
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:
openjdk-8-jdk : Depends: openjdk-8-jre (= 8u171-b11-1~bpo8+1) but it is not …