Several workers wearing hard hats dig a hole.
workers in hard hats dig a hole.
Several workers are workers, and wearing hard hats is a rephrasing of in hard hats.
exists e2 e1 s1 s2 x1 x2 x3 x4.(Theme(e2,x4) & Actor(e2,x1) & v_dig(e2) & n_hole(x4) & Theme(e1,x3) & Actor(e1,x2) & v_wear(e1) & n_hat(x3) & a_hard(s2) & Theme(s2,x3) & (x1 = x2) & n_worker(x1) & a_several(s1) & Theme(s1,x1))
exists e1 s1 x1 x2 x3.(Theme(e1,x3) & Actor(e1,x1) & v_dig(e1) & n_hole(x3) & in(x1,x2) & n_hat(x2) & a_hard(s1) & Theme(s1,x2) & n_worker(x1))