Несколько команд для установки другой Desktop-Environment не помогли

Очень новичок в Ubuntu, я попытался установить две среды рабочего стола (KDE, Cinnamon) несколькими командами в то время как пользователь root, прочитав в Google, как это сделать, но ничего не помогло ... Вот код. Пожалуйста, дайте мне совет,

ben@ben-X58-USB3:~$ su
Password: 
root@ben-X58-USB3:/home/ben# apt-get install kde_desktop
Reading package lists... Done
Building dependency tree       
Reading state information... Done
E: Unable to locate package kde_desktop
root@ben-X58-USB3:/home/ben# apt-get install kde-standart
Reading package lists... Done
Building dependency tree       
Reading state information... Done
E: Unable to locate package kde-standart
root@ben-X58-USB3:/home/ben# apt-get install kde_standart
Reading package lists... Done
Building dependency tree       
Reading state information... Done
E: Unable to locate package kde_standart
root@ben-X58-USB3:/home/ben# apt-get install kde
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Package kde is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package 'kde' has no installation candidate
root@ben-X58-USB3:/home/ben# apt-get install KDE
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Package kde is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package 'kde' has no installation candidate
root@ben-X58-USB3:/home/ben# apt-get install KDE-standart
Reading package lists... Done
Building dependency tree       
Reading state information... Done
E: Unable to locate package KDE-standart
root@ben-X58-USB3:/home/ben#