A dirt bike rider jumps in the air.
Someone is riding a dirt bike
A dirt bike rider is someone.  Jumps in the air implies riding.
exists x1 x2 x3 x4 x5.(n_air(x5) & a_topic(x1) & in(x1,x5) & n_jump(x1) & of(x1,x4) & n_rider(x4) & of(x1,x3) & n_bike(x3) & of(x1,x2) & n_dirt(x2))
exists e1 x1 x2 x3.(Theme(e1,x2) & Actor(e1,x1) & v_ride(e1) & n_bike(x2) & of(x2,x3) & n_dirt(x3) & n_person(x1))