这是我的 /etc/apt/sources.list 内容：
# deb cdrom:[Ubuntu 14.10 _Utopic Unicorn_ - Release amd64 (20141022.1)]/ utopic main restricted
# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://in.archive.ubuntu.com/ubuntu/ utopic main restricted
deb-src http://in.archive.ubuntu.com/ubuntu/ utopic main restricted
## Major bug fix updates produced after the final release of the
## distribution.
deb http://in.archive.ubuntu.com/ubuntu/ utopic-updates main restricted
deb-src http://in.archive.ubuntu.com/ubuntu/ utopic-updates main restricted
## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please …