今天想装gnome3,结果所有的软件源地址都打不开了。新立德打不开，更新管理器提示连接有问题，打开终端显示错误 http://ftp.sjtu.edu.cn dapper-updates/multiverse i386 Packages
404 Not Found
错误 http://ftp.sjtu.edu.cn dapper-updates/restricted i386 Packages
404 Not Found
错误 http://ftp.sjtu.edu.cn dapper-updates/universe i386 Packages
404 Not Found
错误 http://mirrors.163.com natty-updates/universe Sources
404 Not Found [IP: 123.58.173.89 80]
错误 http://mirrors.163.com natty-updates/main Sources
404 Not Found [IP: 123.58.173.89 80]
错误 http://mirrors.163.com natty-updates/multiverse Sources
404 Not Found [IP: 123.58.173.89 80]
错误 http://mirrors.163.com natty-updates/restrict Sources
404 Not Found [IP: 123.58.173.89 80]
错误 http://ppa.launchpad.net oneiric/main Sources
404 Not Found
全都是这样的404~~~
