The children played on the four wheeler in the field.
The people use vehicles.
playing on the four wheeler in the field  does not indicate that people use vehicles.
exists e1 x1 x2 x3.(n_field(x3) & n_wheeler(x2) & card_eq_4(x2) & n_child(x1) & on(e1,x2) & in(x2,x3) & Actor(e1,x1) & v_play(e1))
exists e1 x1 x2.(n_people(x1) & Theme(e1,x2) & Actor(e1,x1) & v_use(e1) & n_vehicle(x2))