A worker in green rakes leaves on a sidewalk.
They are walking.
there  is no indication that there is more than one worker as the word they suggests.
exists e1 s1 x1 x2 x3.(on(e1,x3) & n_sidewalk(x3) & Actor(e1,x1) & v_leave(e1) & in(x1,x2) & n_rake(x2) & a_green(s1) & Theme(s1,x2) & n_worker(x1))
exists e1 x1.(n_thing(x1) & Actor(e1,x1) & v_walk(e1))