Can someone tell me how to make some text with transparent background?

In my Draw() function, I just create:

CWindowGc& gc = SystemGc();
gc.Reset();
gc.DrawText( theText, TPoint(x,y));

using this command, it's copy the screen n make the copied screen as the background.

That I want is the background realy transparent, so every thing that happen in the background we can still see it.
Is int posible?

Thanks before...