deb http://linux.xidian.edu.cn/mirrors/ubuntu/ precise main restricted universe multiverse
#deb-src http://linux.xidian.edu.cn/mirrors/ubuntu/ precise main restricted universe multiverse
deb http://linux.xidian.edu.cn/mirrors/ubuntu/ precise-security main restricted universe multiverse
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deb http://linux.xidian.edu.cn/mirrors/ubuntu/ precise-updates main restricted universe multiverse
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#deb http://linux.xidian.edu.cn/mirrors/ubuntu/ precise-backports main restricted universe multiverse
#deb-src http://linux.xidian.edu.cn/mirrors/ubuntu/ precise-backports main restricted universe multiverse
#deb http://linux.xidian.edu.cn/mirrors/ubuntu/ precise-proposed main restricted universe multiverse
#deb-src http://linux.xidian.edu.cn/mirrors/ubuntu/ precise-proposed main restricted universe multiverse