我开始使用具有以下 source.list 文件的预装操作系统：
deb http://archive.ubuntu.com/ubuntu natty main
deb http://ro.archive.ubuntu.com/ubuntu/ oneiric universe
deb-src http://ro.archive.ubuntu.com/ubuntu/ oneiric universe
deb http://ro.archive.ubuntu.com/ubuntu/ oneiric-updates universe
deb-src http://ro.archive.ubuntu.com/ubuntu/ oneiric-updates universe
我正在尝试将其升级为：
###### Ubuntu Main Repos
deb http://ro.archive.ubuntu.com/ubuntu/ precise main restricted universe multiverse
deb-src http://ro.archive.ubuntu.com/ubuntu/ precise main restricted universe multiverse
###### Ubuntu Update Repos
deb http://ro.archive.ubuntu.com/ubuntu/ precise-security main restricted universe multiverse
deb http://ro.archive.ubuntu.com/ubuntu/ precise-updates main restricted universe multiverse
deb-src http://ro.archive.ubuntu.com/ubuntu/ precise-security main restricted universe multiverse
deb-src http://ro.archive.ubuntu.com/ubuntu/ precise-updates main restricted universe multiverse
但是当我尝试运行 apt-get upgrade 它给了我这个：
root@syrius:/etc/apt# apt-get …