Two dogs are running on the grass.
Two dogs are running after a bird.
Running on the grass does not necessarily mean the dogs are running after a bird.
exists e1 x1 x2.(n_grass(x2) & on(e1,x2) & Actor(e1,x1) & v_run(e1) & n_dog(x1) & card_eq_2(x1))
exists e1 x1 x2.(after(e1,x2) & n_bird(x2) & Actor(e1,x1) & v_run(e1) & n_dog(x1) & card_eq_2(x1))