我错误地卸载了 ubuntu 软件中心和 gvf 包，当我尝试安装 gvf 包时出现此错误。
我跑了 sudo apt-get install gvfs-backends
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:
gvfs-backends : Depends: gvfs (= 1.20.2-1ubuntu3.1) but 1.20.3-0ubuntu1 is to be installed
Depends: gvfs-daemons (= 1.20.2-1ubuntu3.1) but 1.20.3-0ubuntu1 is to be installed
Depends: gvfs-libs (= 1.20.2-1ubuntu3.1) but 1.20.3-0ubuntu1 is to be installed
Depends: gvfs-common (= 1.20.2-1ubuntu3.1) but 1.20.3-0ubuntu1 is to be installed
E: Unable to correct problems, you have held broken packages.
如何解决这一切？