Two boys sitting on a courtyard.
The girls are having a picnic in the courtyard.
Two boys does not refer to girls.
exists e1 x1 x2 x3.(a_topic(x1) & on(e1,x3) & n_courtyard(x3) & Actor(e1,x2) & v_sit(e1) & (x1 = x2) & n_boy(x1) & card_eq_2(x1))
exists e1 x1 x2 x3.(n_courtyard(x3) & n_girl(x1) & in(e1,x3) & Theme(e1,x2) & Actor(e1,x1) & v_have(e1) & n_picnic(x2))