People sit on benches.
People sit on benches while children play on a playground.
Sitting on benches does not mean that children play on a playground.
exists e1 x1 x2.(on(e1,x2) & n_bench(x2) & Actor(e1,x1) & v_sit(e1) & n_people(x1))
exists e1 p1 x1 x2.(exists e2 x3 x4.(on(e2,x4) & n_playground(x4) & Actor(e2,x3) & v_play(e2) & n_child(x3)) & while(e1,p1) & on(e1,x2) & n_bench(x2) & Actor(e1,x1) & v_sit(e1) & n_people(x1))