Two people are playing on a teeter totter.
a couple play on teeter totter
the two people may or may not be a couple.
exists e1 x1 x2 x3.(on(e1,x2) & n_totter(x2) & of(x2,x3) & n_teeter(x3) & Actor(e1,x1) & v_play(e1) & n_people(x1) & card_eq_2(x1))
exists x1 x2 x3 x4.(a_topic(x1) & on(x1,x3) & n_totter(x3) & of(x3,x4) & n_teeter(x4) & n_play(x1) & of(x1,x2) & n_couple(x2))