Four children are playing on a hill of sand.
Four children are playing quietly.
Four children playing aren't always playing quietly.
exists e1 x1 x2 x3.(on(e1,x2) & of(x2,x3) & n_sand(x3) & n_hill(x2) & Actor(e1,x1) & v_play(e1) & n_child(x1) & card_eq_4(x1))
exists e1 s1 x1.(a_quietly(s1) & Manner(e1,s1) & Actor(e1,x1) & v_play(e1) & n_child(x1) & card_eq_4(x1))