Someone in a helmet doing a jump on a bike over a large mound of dirt.
A person is riding a bike on a dangerous course.
The jump may not be part of a course.  The bike ride may not be dangerous.
exists e1 s1 x1 x2 x3 x4 x5 x6 x7.(a_topic(x1) & in(x1,x2) & Theme(e1,x4) & Actor(e1,x3) & v_do(e1) & over(x4,x6) & of(x6,x7) & n_dirt(x7) & n_mound(x6) & a_large(s1) & Theme(s1,x6) & on(x4,x5) & n_bike(x5) & n_jump(x4) & (x2 = x3) & n_helmet(x2) & n_person(x1))
exists e1 s1 x1 x2 x3.(on(e1,x3) & n_course(x3) & a_dangerous(s1) & Theme(s1,x3) & Theme(e1,x2) & Actor(e1,x1) & v_ride(e1) & n_bike(x2) & n_person(x1))