A dog in a field.
A dog is chasing a ball.
The fact that the dog is in a field does not mean that he is chasing a ball.
exists x1 x2.(a_topic(x1) & in(x1,x2) & n_field(x2) & n_dog(x1))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_chase(e1) & n_ball(x2) & n_dog(x1))