A small white dog runs across the sand.
Some sand has a dog on it.
The dog running across the sand is another way of saying that the dog is on top of the sand.
exists e1 s1 s2 x1 x2.(n_sand(x2) & across(e1,x2) & Actor(e1,x1) & v_run(e1) & n_dog(x1) & a_white(s2) & Theme(s2,x1) & a_small(s1) & Theme(s1,x1))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_have(e1) & on(x2,x1) & n_thing(x1) & n_dog(x2) & n_sand(x1))