Two children playing on a jungle gym.
nobody is playing.
Nobody is playing then the two children cannot be on the jungle gym.
exists e1 x1 x2 x3 x4.(a_topic(x1) & on(e1,x3) & n_gym(x3) & of(x3,x4) & n_jungle(x4) & Actor(e1,x2) & v_play(e1) & (x1 = x2) & n_child(x1) & card_eq_2(x1))
-exists e1 x1.(Actor(e1,x1) & v_play(e1) & n_person(x1))