A worker walking down the street.
A worker is whistling while he walks.
A worker walking doesn't imply they are whistling.
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 e1 p1 x1.(exists e2.(Actor(e2,x1) & v_walk(e2)) & n_male(x1) & while(e1,p1) & Actor(e1,x1) & v_whistle(e1) & n_worker(x1))