A marching band performs on the field.
A marching band is practicing before the football game.
A band can perform without practicing first and can perform at many events besides football games.
exists e1 x1 x2 x3.(n_field(x3) & a_topic(x1) & on(x1,x3) & n_perform(x1) & of(x1,x2) & n_band(x2) & Actor(e1,x1) & v_march(e1))
exists e1 e2 x1 x2 x3.(n_game(x2) & of(x2,x3) & n_football(x3) & before(e2,x2) & Actor(e2,x1) & v_practice(e2) & n_band(x1) & Actor(e1,x1) & v_march(e1))