The two kids are playing at the playground.
Two children are on a swingset.
Two kids playing at a playground may not be on a swingset.
exists e1 x1 x2.(n_playground(x2) & n_kid(x1) & card_eq_2(x1) & at(e1,x2) & Actor(e1,x1) & v_play(e1))
exists p1 x1.(exists x2.(on(x1,x2) & n_swingset(x2)) & n_child(x1) & card_eq_2(x1))