Four people are walking on a bridge.
The people walk on the bridge.
"People are walking on the bridge" is a rephrasing of "the people walk on the bridge".
exists e1 x1 x2.(on(e1,x2) & n_bridge(x2) & Actor(e1,x1) & v_walk(e1) & n_people(x1) & card_eq_4(x1))
exists e1 x1 x2.(n_bridge(x2) & n_people(x1) & on(e1,x2) & Actor(e1,x1) & v_walk(e1))