linux中apt-get不能使用可能因爲源不對，需要修改/etc/apt下的sources.list文件
apt-get源網上有很多，但是試了很多都不能用，以下提供一個我自己這邊使用成功的源：
deb http://cn.archive.ubuntu.com/ubuntu/ lucid main restricted
deb-src http://cn.archive.ubuntu.com/ubuntu/ lucid main restricted
deb http://cn.archive.ubuntu.com/ubuntu// lucid-updates main restricted
deb-src http://cn.archive.ubuntu.com/ubuntu// lucid-updates main restricted
deb http://cn.archive.ubuntu.com/ubuntu/ lucid universe
deb-src http://cn.archive.ubuntu.com/ubuntu/ lucid universe
deb http://cn.archive.ubuntu.com/ubuntu/ lucid-updates universe
deb-src http://cn.archive.ubuntu.com/ubuntu/ lucid-updates universe
deb http://cn.archive.ubuntu.com/ubuntu/ lucid multiverse
deb-src http://cn.archive.ubuntu.com/ubuntu/ lucid multiverse
deb http://cn.archive.ubuntu.comm/ubuntu/ lucid-updates multiverse
deb-src http://cn.archive.ubuntu.comm/ubuntu/ lucid-updates multiverse
deb http://security.ubuntu.com/ubuntu lucid-security main restricted
deb-src http://security.ubuntu.com/ubuntu lucid-security main restricted
deb http://security.ubuntu.com/ubuntu lucid-security universe
deb-src http://security.ubuntu.com/ubuntu lucid-security universe
deb http://security.ubuntu.com/ubuntu lucid-security multiverse
deb-src http://security.ubuntu.com/ubuntu lucid-security multiverse