bull rider on the ground
The person fell off the bull.
Just because the bull rider is on the ground doesn't mean they fell off the bull.
exists x1 x2 x3.(n_ground(x3) & a_topic(x1) & on(x1,x3) & n_rider(x1) & of(x1,x2) & n_bull(x2))
exists e1 s1 x1 x2.(n_bull(x2) & n_person(x1) & a_off(s1) & Manner(e1,s1) & Theme(e1,x2) & Actor(e1,x1) & v_fall(e1))