Two soccer players on a soccer field.
Two baseball players are on a soccer field.
The two players are either baseball players or soccer players, but cannot be both simultaneously.
exists x1 x2 x3 x4.(a_topic(x1) & on(x1,x3) & n_field(x3) & of(x3,x4) & n_soccer(x4) & n_player(x1) & of(x1,x2) & n_soccer(x2) & card_eq_2(x1))
exists p1 x1 x2.(exists x3 x4.(on(x1,x3) & n_field(x3) & of(x3,x4) & n_soccer(x4)) & n_player(x1) & of(x1,x2) & n_baseball(x2) & card_eq_2(x1))