A black dog tugs on a rope.
The white dog is rugging on the rope.
The black dog has it or the white dog, not both.
exists s1 x1 x2 x3.(a_topic(x1) & on(x1,x3) & n_rope(x3) & n_tug(x1) & of(x1,x2) & n_dog(x2) & a_black(s1) & Theme(s1,x1))
exists e1 s1 x1 x2.(n_rope(x2) & n_dog(x1) & a_white(s1) & Theme(s1,x1) & on(e1,x2) & Actor(e1,x1) & v_rugg(e1))