A man is using a jackhammer to work on a sidewalk.
A construction worker is breaking up concrete.
One can't assume that a man using a jackhammer is necessarily a construction worker.  Just because a man is using a jackhammer to work on a sidewalk, doesn't imply he is breaking up concrete.  The sidewalk might not be made of concrete.
exists e1 p1 x1 x2.(Theme(e1,p1) & Recipient(e1,x2) & Actor(e1,x1) & v_use(e1) & exists e2 x3.(on(e2,x3) & n_sidewalk(x3) & Actor(e2,x1) & v_work(e2)) & n_jackhammer(x2) & n_man(x1))
exists e1 s1 x1 x2 x3.(a_up(s1) & Manner(e1,s1) & Theme(e1,x3) & Actor(e1,x1) & v_break(e1) & n_concrete(x3) & n_worker(x1) & of(x1,x2) & n_construction(x2))