从以下各服务器列表内容中选择一段替换文件中的所有内容，为防止非官方源中软件包不全的问题，请在sources.list文件中尾部添加一组官方源
* . Archive.Ubuntu.com 更新服务器(欧洲，此为官方源，推荐使用。)：
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deb feisty main restricted universe multiverse
deb feisty-security main restricted universe multiverse
deb feisty-updates main restricted universe multiverse
deb feisty-proposed main restricted universe multiverse
deb feisty-backports main restricted universe multiverse
deb-src feisty main restricted universe multiverse
deb-src feisty-security main restricted universe multiverse
deb-src feisty-updates main restricted universe multiverse
deb-src feisty-proposed main restricted universe multiverse
deb-src feisty-backports main restricted universe multiverse
o Ubuntu.cn99.com 更新服务器(江苏省常州市电信，推荐电信用户使用。）
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deb feisty main restricted universe multiverse
deb feisty-security main restricted universe multiverse
deb feisty-updates main restricted universe multiverse
deb feisty-proposed main restricted universe multiverse
deb feisty-backports main restricted universe multiverse
deb-src feisty main restricted universe multiverse
deb-src feisty-security main restricted universe multiverse
deb-src feisty-updates main restricted universe multiverse
deb-src feisty-proposed main restricted universe multiverse
deb-src feisty-backports main restricted universe multiverse
deb feisty main restricted universe multiverse
o Mirror.lupaworld.com 更新服务器(浙江省杭州市电信，亚洲地区官方更新服务器，推荐全国用户使用。）：
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deb feisty main restricted universe multiverse
deb feisty-security main restricted universe multiverse
deb feisty-updates main restricted universe multiverse
deb feisty-backports main restricted universe multiverse
deb feisty-proposed main restricted universe multiverse
deb-src feisty main restricted universe multiverse
deb-src feisty-security main restricted universe multiverse
deb-src feisty-updates main restricted universe multiverse
deb-src feisty-backports main restricted universe multiverse
deb-src feisty-proposed main restricted universe multiverse
o 上海市 上海交通大学 更新服务器（教育网，推荐校园网和网通用户使用。）(目前已无法使用)：
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deb feisty main multiverse restricted universe
deb feisty-backports main multiverse restricted universe
deb feisty-proposed main multiverse restricted universe
deb feisty-security main multiverse restricted universe
deb feisty-updates main multiverse restricted universe
deb-src feisty main multiverse restricted universe
deb-src feisty-backports main multiverse restricted universe
deb-src feisty-proposed main multiverse restricted universe
deb-src feisty-security main multiverse restricted universe
deb-src feisty-updates main multiverse restricted universe
o 北京市清华大学 更新服务器（教育网，推荐校园网和网通用户使用。)：
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deb feisty main multiverse restricted universe
deb feisty-backports main multiverse restricted universe
deb feisty-proposed main multiverse restricted universe
deb feisty-security main multiverse restricted universe
deb feisty-updates main multiverse restricted universe
deb-src feisty main multiverse restricted universe
deb-src feisty-backports main multiverse restricted universe
deb-src feisty-proposed main multiverse restricted universe
deb-src feisty-security main multiverse restricted universe
deb-src feisty-updates main multiverse restricted universe