expand_answer -- how to use??

From: Joe (jmv2_at_duke.edu)
Date: 10/06/04 

Date: Wed, 06 Oct 2004 09:41:31 -0400

I am a prolog newbie, and am having no lukc getting the SWI-prolog
"expand_answer" predicate to work. anyone know how to do this??
i am trying to find out the specific facts that prolog used to find
descendants in a heirarchy. is there another way to do this?