Four girls sit on an ATV in a yard.
Some girls are sitting on a four wheeler.
Some girls could mean four girls, and a four wheel is an ATV.
exists e1 x1 x2 x3.(in(e1,x3) & n_yard(x3) & on(e1,x2) & ne_org_atv(x2) & Actor(e1,x1) & v_sit(e1) & n_girl(x1) & card_eq_4(x1))
exists e1 x1 x2.(on(e1,x2) & n_wheeler(x2) & card_eq_4(x2) & Actor(e1,x1) & v_sit(e1) & n_girl(x1))