Some motorcyclists make a jump in a dirt bike race.
People on motorcycles.
Motorcyclists are people who ride motorcycles. To make a jump in a race, a motorcyclist would have to be on his or her motorcycle at that time.
exists e1 x1 x2 x3 x4 x5.(Theme(e1,x2) & Actor(e1,x1) & v_make(e1) & in(x2,x3) & n_race(x3) & of(x3,x5) & n_bike(x5) & of(x3,x4) & n_dirt(x4) & n_jump(x2) & n_motorcyclist(x1))
exists x1 x2.(a_topic(x1) & on(x1,x2) & n_motorcycle(x2) & n_people(x1))