A person performs a stunt with a bike.
The stunt person is riding a skateboard.
A man cannot be doing stunt with a bike and riding a skateboard at the same time.
exists e1 x1 x2 x3.(with(e1,x3) & n_bike(x3) & Theme(e1,x2) & Actor(e1,x1) & v_perform(e1) & n_stunt(x2) & n_person(x1))
exists e1 x1 x2 x3.(n_person(x1) & of(x1,x2) & n_stunt(x2) & Theme(e1,x3) & Actor(e1,x1) & v_ride(e1) & n_skateboard(x3))