Dogs fight in grass over toy.
Some dogs are fighting each other.
If two dogs are fighting each other then they could be fighting for many more reasons than for possession of a toy.
exists e1 x1 x2 x3 x4.(in(e1,x3) & over(x3,x4) & n_toy(x4) & n_grass(x3) & Theme(e1,x2) & Actor(e1,x1) & v_fight(e1) & n_thing(x2) & n_dog(x1))
exists x1.(all x2.(n_other(x2) -> exists e1.(Theme(e1,x2) & Actor(e1,x1) & v_fight(e1))) & n_dog(x1))