some question about apt-get source

[loody]

Dear all:
I try to get some source file as I need, like gcc and xorg, so I try
to use "sudo apt-get source gcc" and "sudo apt-get source xorg".
But I find what I get are *.dsc and *.gz 2 files and I find the file
after taring the gz is not what I want.

gcc-defaults_1.74ubuntu2.dsc
gcc-defaults_1.74ubuntu2.tar.gz
xorg_7.4~5ubuntu3.dsc
xorg_7.4~5ubuntu3.tar.gz

Does that mean I should get really source by  the dsc and gz files?
or I use the wrong way to get source code?
(xorg should use git, etc.)
appreciate your help,
miloody