A man is sitting looking at water.
A man is on a boat.
A man sitting looking at water is not necessarily on a boat.
exists e1 e2 x1 x2.(for(e1,e2) & at(e2,x2) & n_water(x2) & Actor(e2,x1) & v_look(e2) & Actor(e1,x1) & v_sit(e1) & n_man(x1))
exists p1 x1.(exists x2.(on(x1,x2) & n_boat(x2)) & n_man(x1))