A dog is leaping through the grass.
A dog is leaping after his toy.
Just because a dog is leaping in the grass does not mean it is after his toy.
exists e1 x1 x2.(n_grass(x2) & through(e1,x2) & Actor(e1,x1) & v_leap(e1) & n_dog(x1))
exists e1 x1 x2.(after(e1,x2) & n_toy(x2) & of(x2,x1) & n_male(x1) & Actor(e1,x1) & v_leap(e1) & n_dog(x1))