A group of children are playing on swings.
Some humans
Some group of children are playing
exists e1 x1 x2 x3.(on(e1,x3) & n_swing(x3) & Actor(e1,x1) & v_play(e1) & of(x1,x2) & n_child(x2) & n_group(x1))
exists x1.(a_topic(x1) & n_human(x1))