Linux apt-get source configuration

In linux apt-get source configuration, apt-get cannot be used in linux. It may be because the source is incorrect. You need to modify sources under/etc/apt. the list file apt-get has many sources on the Internet, but many of them cannot be used. The following provides a source that is successfully used by myself: deb http://cn.archive.ubuntu.com/ubuntu/ lucid main supply-src http://cn.archive.ubuntu.com/ubuntu/ lucid main restricteddeb http://cn.archive.ubuntu.com/ubuntu// lucid-updates main supply-src http://cn.archive.ubuntu.com/ubuntu// lucid-updates main supply http://cn.archive.ubuntu.com/ubuntu/ lucid universedeb-src http://cn.archive.ubuntu.com/ubuntu/ lucid universedeb http://cn.archive.ubuntu.com/ubuntu/ lucid-updates universedeb-src http://cn.archive.ubuntu.com/ubuntu/ lucid-updates universedeb http://cn.archive.ubuntu.com/ubuntu/ lucid multiversedeb-src http://cn.archive.ubuntu.com/ubuntu/ lucid multiversedeb http://cn.archive.ubuntu.comm/ubuntu/ lucid-updates multiversedeb-src http://cn.archive.ubuntu.comm/ubuntu/ lucid-updates multiversedeb http://security.ubuntu.com/ubuntu lucid-security main supply-src http://security.ubuntu.com/ubuntu lucid-security main http://security.ubuntu.com/ubuntu lucid-security universedeb-src http://security.ubuntu.com/ubuntu lucid-security universedeb http://security.ubuntu.com/ubuntu lucid-security multiversedeb-src http://security.ubuntu.com/ubuntu lucid-security multiverse