two people sit on a bench.
Two friends are sitting on a bench.
We do not know that two people sitting on a bench are friends or even if they know each other.
exists e1 x1 x2.(on(e1,x2) & n_bench(x2) & Actor(e1,x1) & v_sit(e1) & n_people(x1) & card_eq_2(x1))
exists e1 x1 x2.(on(e1,x2) & n_bench(x2) & Actor(e1,x1) & v_sit(e1) & n_friend(x1) & card_eq_2(x1))