A boy is airborne on a bicycle above an urban walkway near a handrail.
A boy riding his skateboard on the walkway.
The boy is either riding a bicycle OR a skateboard. If he is airborne he is not "on" the walkway.
exists s1 s2 x1 x2 x3 x4.(on(s1,x2) & above(x2,x3) & near(x3,x4) & n_handrail(x4) & n_walkway(x3) & a_urban(s2) & Theme(s2,x3) & n_bicycle(x2) & Theme(s1,x1) & a_airborne(s1) & n_boy(x1))
exists e1 x1 x2 x3 x4.(n_walkway(x4) & a_topic(x1) & on(e1,x4) & Theme(e1,x3) & Actor(e1,x2) & v_ride(e1) & n_skateboard(x3) & of(x3,x1) & n_male(x1) & (x1 = x2) & n_boy(x1))