Two girls talking while sitting on the stairs.
Two girls sit on the stairs in the school.
Not all girls sitting on the stairs are at school.
exists e1 e2 x1 x2 x3.(n_stair(x3) & a_topic(x1) & while(e1,e2) & on(e2,x3) & Actor(e2,x2) & v_sit(e2) & Actor(e1,x2) & v_talk(e1) & (x1 = x2) & n_girl(x1) & card_eq_2(x1))
exists e1 x1 x2 x3.(n_school(x3) & n_stair(x2) & in(e1,x3) & on(e1,x2) & Actor(e1,x1) & v_sit(e1) & n_girl(x1) & card_eq_2(x1))