A dog rolls on his back in the grass.
The dog is digging a hole
he can't be both rolling on his back and digging a hole.
exists e1 x1 x2 x3.(n_grass(x3) & in(e1,x3) & on(e1,x2) & n_back(x2) & of(x2,x1) & n_male(x1) & Actor(e1,x1) & v_roll(e1) & n_dog(x1))
exists e1 x1 x2.(n_dog(x1) & Theme(e1,x2) & Actor(e1,x1) & v_dig(e1) & n_hole(x2))