A dog is digging a hole in the sand.
A cat digs in its litter box.
A dog is by definition not a cat.
exists e1 x1 x2 x3.(n_sand(x3) & in(e1,x3) & Theme(e1,x2) & Actor(e1,x1) & v_dig(e1) & n_hole(x2) & n_dog(x1))
exists e1 x1 x2 x3.(in(e1,x2) & n_box(x2) & of(x2,x3) & n_litter(x3) & of(x2,x1) & n_thing(x1) & Actor(e1,x1) & v_dig(e1) & n_cat(x1))