apt-get install 无法安装问题

刚刚装了基本系统，用apt-get 安装不了东西！！！
比如，输入“apt-get install zhcon” 出现一堆乱七八糟的东西，然后，如果输入zhcon，就显示command not found
用apt-get install 很多东西都是这样，是不是apt-get 有什么问题了？
sources.list里我加的是科大的源

应该查看一下源的格式！

# z42.de
deb http://z42.de/ debian/

# http://www.sonsuzdongu.com
# deb http://www.sonsuzdongu.com/paketler ././

# http://debian.neo.pl/
# deb http://debian.neo.pl/wfmh ./
#──────────────────────────────────────────────────
# 教育网
#----------------------------------------------------------------------------------------
# debian.ustc.edu.cn 210.45.66.210
deb http://debian.ustc.edu.cn/debian/ unstable main non-free contrib
deb http://debian.ustc.edu.cn/debian-non-US/ unstable/non-US main non-free contrib
deb http://debian.ustc.edu.cn/debian-uo/ sid java marillat rareware misc ustc

# mirror.dlut.edu.cn 202.118.66.14
deb http://mirror.dlut.edu.cn/debian/ unstable main contrib non-free
deb http://mirror.dlut.edu.cn/debian-non-US/ unstable/non-US main contrib non-free

# ftp.linuxforum.net 61.152.210.194
deb ftp://ftp.linuxforum.net/debian/ unstable main non-free contrib
deb ftp://ftp.linuxforum.net/debian-non-US/ unstable/non-US main non-free contrib

# mirrors.geekbone.org 61.172.200.169
# deb http://mirrors.geekbone.org/debian/ unstable main non-free contrib
# deb http://mirrors.geekbone.org/debian-non-US/ unstable/non-US main non-free contrib

# debian.cn99.com 61.132.102.124
deb http://debian.cn99.com/debian/ unstable main non-free contrib
deb http://debian.cn99.com/debian-non-US/ unstable/non-US main non-free contrib

以上是我现在的源

貌似有问题，注释掉试试。