a boy is standing on a sewer tube for fun.
A boy crawls through the tube.
The boy cannot be standing and crawl at the same time.
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.(n_tube(x2) & through(e1,x2) & Actor(e1,x1) & v_crawl(e1) & n_boy(x1))