City workers are working on the subway.
city workers are working
working on the subway  shows that  city workers are working
exists e1 x1 x2 x3.(n_subway(x3) & on(e1,x3) & Actor(e1,x1) & v_work(e1) & n_worker(x1) & (x1 = x2) & ne_geo_city(x2))
exists e1 x1 x2.(Actor(e1,x1) & v_work(e1) & n_worker(x1) & of(x1,x2) & n_city(x2))