I installed the Ubuntu 12.04 then I reinstalled Ubuntu 12.10 (the version along with Window 7) When I was using Ubuntu 12.04, I typed
ls to show what file are listed in directory(included arm-linux-gcc-4.5.1-v6-vfp-20120301.tgz) And the list show out the file that are needed to be extracted. And that i type
sudo tar -zxvf arm-linux-gcc-4.5.1-v6-vfp-20120301.tgz -C / and file was extracted in the same directory with zip file and own by user. After i install Ubuntu 12.10 redo the processes
ls(check file again)
sudo tar -zxvf arm-linux-gcc-4.5.1-v6-vfp-20120301.tgz -C /and the extracted file was in the File System and owned by root and adminstrator can't use it.