A sheriff on a motorcycle leads a parade.
An officer on a motorcycle
Officer is another term for sheriff.
exists e1 x1 x2 x3.(Theme(e1,x3) & Actor(e1,x1) & v_lead(e1) & n_parade(x3) & on(x1,x2) & n_motorcycle(x2) & n_sheriff(x1))
exists x1 x2.(a_topic(x1) & on(x1,x2) & n_motorcycle(x2) & n_officer(x1))