A woman stands looking at art on the wall.
A woman is sitting on a roof.
The woman can't be sitting while she stands.
exists e2 e1 x1 x2 x3.(n_wall(x3) & for(e1,e2) & on(e2,x3) & at(e2,x2) & n_art(x2) & Actor(e2,x1) & v_look(e2) & Actor(e1,x1) & v_stand(e1) & n_woman(x1))
exists e1 x1 x2.(on(e1,x2) & n_roof(x2) & Actor(e1,x1) & v_sit(e1) & n_woman(x1))