A bus occupied by asians.
The bus is occupied by puppies.
The bus can only be occupied by either asians or puppies but not both.
exists e1 x1 x2 x3.(a_topic(x1) & Actor(e1,x3) & n_asian(x3) & Theme(e1,x2) & v_occupy(e1) & (x1 = x2) & n_bus(x1))
exists e1 x1 x2.(n_bus(x1) & Actor(e1,x2) & n_puppy(x2) & Theme(e1,x1) & v_occupy(e1))