A construction worker works is welding.
A human working
Construction worker is a human, and welding is another kind of working.
exists e2 e1 x1 x2 x3.(Actor(e2,x1) & v_weld(e2) & Actor(e1,x3) & v_work(e1) & (x1 = x3) & n_worker(x1) & of(x1,x2) & n_construction(x2))
exists s1 s2 x1.(a_topic(s1) & of(s1,x1) & n_working(x1) & a_human(s2) & Theme(s2,s1))