我需要安装 qtbase5-dev，但是
$> sudo apt-get install qtbase5-dev
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:
qtbase5-dev : Depends: libgles2-mesa-dev or
libgles2-dev but it is not installable
我追溯到：
$ sudo apt-get install libwayland-dev
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:
libwayland-dev : Depends: libwayland-client0 (= 1.4.0-1ubuntu1) but 1.7.0-0ubuntu1~trusty1 is to be installed
Depends: libwayland-server0 (= 1.4.0-1ubuntu1) but 1.7.0-0ubuntu1~trusty1 is to be installed
Depends: libwayland-cursor0 (= 1.4.0-1ubuntu1) but 1.7.0-0ubuntu1~trusty1 is to be installed
E: Unable to correct problems, you have held broken packages.
我安装了状况良好的（近~24 小时没有任何手动更改，只有 apt-get install）ubuntu-gnome 14.04.2。
因为我需要能够使用 pyqt5，它依赖于 qt5-default，而 qt5-default 又依赖于 gt5base-dev，所以我很想知道我该如何解决这种情况？
我可以安装旧版本的软件包吗？
答案1
我通过安装“旧”的 ubuntu 14.04（no .2）“修复”了该问题 - 该问题不再出现。