a boy is standing on a sewer tube for fun.
A boy is having fun on a sewer tube.
A boy on a sewer tube for fun is rephrasing of fun on sewer tube.
exists e1 x1 x2 x3 x4.(for(e1,x4) & n_fun(x4) & on(e1,x2) & n_tube(x2) & of(x2,x3) & n_sewer(x3) & Actor(e1,x1) & v_stand(e1) & n_boy(x1))
exists e1 x1 x2 x3 x4.(on(e1,x3) & n_tube(x3) & of(x3,x4) & n_sewer(x4) & Theme(e1,x2) & Actor(e1,x1) & v_have(e1) & n_fun(x2) & n_boy(x1))