A cowboy riding on the back of a bronco in a competition.
the cowboy rode the sheep
A sheep is not a bronco.
exists s1 x1 x2 x3 x4.(n_back(x2) & a_topic(x1) & on(x1,x2) & of(x2,x3) & in(x3,x4) & n_competition(x4) & n_bronco(x3) & n_riding(x1) & a_cowboy(s1) & Theme(s1,x1))
exists e1 x1 x2.(n_sheep(x2) & n_cowboy(x1) & Theme(e1,x2) & Actor(e1,x1) & v_ride(e1))