首先，我使用的是最新版本 20.04（Linux 内核 5.4.0-48-generic）。我尝试安装一些应用程序，例如 Spotify、Discord、Steam……它们都给我这些库错误。为什么会发生这种情况以及如何解决？
对于 Spotify：
The following packages have unmet dependencies:
spotify-client: Dependencies: libgconf-2-4 but it is not installable
libavcodec57 but it is not installable or
libavcodec-extra57 but it is not installable or
libavcodec-ffmpeg56 but it is not installable or
libavcodec-ffmpeg-extra56 but it is not installable or
libavcodec54 but it is not installable or
libavcodec-extra-54 but it is not installable
Reccomends: libavformat57 but it is not installable or
libavformat-ffmpeg56 but it is not installable or
libavformat54 but it is not installable
对于 Steam：
The following packages have unmet dependencies:
steam: Dependencies: libgl1-mesa-dri (>= 17.3) but it is not going to be installed or
libtxc-dxtn0 but it is not installable
Dependencies: libgl1-mesa-glx but it is not going to be installed
Recomends: mesa-vulkan-drivers but it is not going to be installed
Recomends: mesa-vulkan-drivers:i386
对于Discord：
The following packages have unmet dependencies:
discord: Dependencies: libgconf-2-4 but it is not installable
Dependencies: libappindicator1 but it is not installable
Dependencies: libc++1 but it is not installable
所有应用程序都给我类似的错误。甚至现在除了浏览互联网之外都无法使用。
请帮忙。
顺便说一句，这是全新安装。我几个小时前才下载的。