A boy doing a trick on top of a guard rail on inline skates.
A girl is riding a horse.
A boy isn't the same as a girl and they cannot ride a horse on a guard rail.
exists e1 x1 x2 x3 x4 x5 x6 x7 x8.(a_topic(x1) & Theme(e1,x3) & Actor(e1,x2) & v_do(e1) & on(x3,x4) & of(x4,x5) & on(x5,x7) & n_skate(x7) & of(x7,x8) & n_inline(x8) & n_rail(x5) & of(x5,x6) & n_guard(x6) & n_top(x4) & n_trick(x3) & (x1 = x2) & n_boy(x1))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_ride(e1) & n_horse(x2) & n_girl(x1))