Two adults on cellphones downtown.
two adults are on the phone.
Though sentence two says they are on their phone, this describes in the two adults who are on their cell phones downtown.
exists x1 x2 x3.(a_topic(x1) & on(x1,x2) & n_downtown(x2) & of(x2,x3) & n_cellphone(x3) & n_adult(x1) & card_eq_2(x1))
exists p1 x1 x2.(n_phone(x2) & on(x1,x2) & n_adult(x1) & card_eq_2(x1))