Need answer soon

[Gefox4]

When I choose Add/Remove, then I choose some packages and click OK, the packages will be download and install. But where will the packages be in??? :confused:

[5-HT]

The .debs themselves will be downloaded to /var/cache/apt/archives/
As to the installed files, they will be installed into various places in the filesystem as stipulated by the package itself--usually with the bulk in /usr. To see where individual files of a package are placed you can use synaptic (look in the right-click properties tab for a package) or by using the 'whereis' command (refer to 'man whereis' from a terminal for futher information).