A dog jumps over the sand.
A dog jumps on the sand.
One can't jump over and on at the same time.
exists e1 x1 x2.(n_sand(x2) & over(e1,x2) & Actor(e1,x1) & v_jump(e1) & n_dog(x1))
exists e1 x1 x2.(n_sand(x2) & on(e1,x2) & Actor(e1,x1) & v_jump(e1) & n_dog(x1))