A worker walking down the street.
A worker walking down the street while humming.
Not all workers walking down the street are humming.
exists e1 x1 x2 x3.(n_street(x3) & a_topic(x1) & down(e1,x3) & Actor(e1,x2) & v_walk(e1) & (x1 = x2) & n_worker(x1))
exists e2 e1 x1 x2 x3.(n_street(x3) & a_topic(x1) & while(e1,e2) & Actor(e2,x2) & v_hum(e2) & down(e1,x3) & Actor(e1,x2) & v_walk(e1) & (x1 = x2) & n_worker(x1))