Construction workers work on an unfinished building.
Workers attempting to complete building constructions.
If people are "attempting to complete building constructions", then they are doing "work on an unfinished building".
exists e1 s1 x1 x2 x3.(on(e1,x3) & n_building(x3) & a_unfinished(s1) & Theme(s1,x3) & Actor(e1,x1) & v_work(e1) & n_worker(x1) & of(x1,x2) & n_construction(x2))
exists e1 p1 x1.(Topic(e1,p1) & Actor(e1,x1) & v_attempt(e1) & exists e2 x2 x3.(Theme(e2,x2) & Actor(e2,x1) & v_complete(e2) & n_construction(x2) & of(x2,x3) & n_building(x3)) & n_worker(x1))