Two people are at a park.
Two sad people are at a park.
People are not always sad.
exists p1 x1.(exists x2.(at(x1,x2) & n_park(x2)) & n_people(x1) & card_eq_2(x1))
exists p1 s1 x1.(exists x2.(at(x1,x2) & n_park(x2)) & n_people(x1) & a_sad(s1) & Theme(s1,x1) & card_eq_2(x1))