Policeman standing next to his motorcycle.
The policeman is riding the motorcycle.
You cannot be standing and riding.
exists e1 x1 x2.(n_motorcycle(x2) & of(x2,x1) & n_male(x1) & ne_nam_policeman(x1) & to(e1,x2) & r_next(e1) & Actor(e1,x1) & v_stand(e1))
exists e1 x1 x2.(n_motorcycle(x2) & n_policeman(x1) & Theme(e1,x2) & Actor(e1,x1) & v_ride(e1))