A small black dog playing with a ball in the grass.
A dog is playing in the grass.
When a dog is playing with a ball in the grass, the dog is playing in the grass, but the ball is not playing.
exists s1 s2 x1 x2 x3 x4.(n_grass(x4) & a_topic(x1) & with(x1,x3) & in(x3,x4) & n_ball(x3) & n_playing(x1) & of(x1,x2) & n_dog(x2) & a_black(s2) & Theme(s2,x1) & a_small(s1) & Theme(s1,x1))
exists e1 x1 x2.(n_grass(x2) & in(e1,x2) & Actor(e1,x1) & v_play(e1) & n_dog(x1))