A boy doing a back flip off of a sand dune.
A boy is going to land the back flip.
Just because a boy is doing a back flip does not mean that he is going to land it.
exists e1 s1 x1 x2 x3 x4 x5 x6.(a_topic(x1) & of(e1,x5) & n_dune(x5) & of(x5,x6) & n_sand(x6) & r_off(e1) & Theme(e1,x3) & Actor(e1,x2) & v_do(e1) & Theme(s1,x4) & a_flip(s1) & (x3 = x4) & n_back(x3) & (x1 = x2) & n_boy(x1))
exists e1 p1 s1 x1 x2.(n_flip(x2) & a_back(s1) & Theme(s1,x2) & Topic(e1,p1) & Actor(e1,x1) & v_go(e1) & exists e2.(Theme(e2,x2) & Actor(e2,x1) & v_land(e2)) & n_boy(x1))