editing an existing predicate, select the predicate from the predicate
list, then it's content will appear in the edit window. Repeat previous
procedure to edit.</tt></li>

<li>
<tt>Repeat previous procedure to built 5 predicates, at_bag(bag,place),
at_thing(thing,place), inside(thing,bag), fits_in(thing,bag), outside_at(thing,place),
shown in the following figure. Select the predicate "fits_in(thing,bag)",
click the check box "Is Static" to make it static.</tt></li>

<li>
<tt>To delete a predicate, first s