a group of children are standing outside a building.
A group of children are waiting for their parents.
Just because children are standing outside a building doesn't mean they're waiting for their parents.
exists e1 x1 x2 x3.(outside(e1,x3) & n_building(x3) & Actor(e1,x1) & v_stand(e1) & of(x1,x2) & n_child(x2) & n_group(x1))
exists e1 x1 x2 x3.(for(e1,x3) & n_parent(x3) & of(x3,x1) & n_thing(x1) & Actor(e1,x1) & v_wait(e1) & of(x1,x2) & n_child(x2) & n_group(x1))