Workers standing in a work zone.
Workers are hard at work
Workers standing in work zone may or not be hard at work.
exists e1 x1 x2 x3.(in(e1,x2) & n_zone(x2) & of(x2,x3) & n_work(x3) & Actor(e1,x1) & v_stand(e1) & n_worker(x1))
exists s1 x1 x2.(at(s1,x2) & n_work(x2) & Theme(s1,x1) & a_hard(s1) & n_worker(x1))