A man wearing safety gear is using a weed whacker.
The man  is trimming his hedges.
Just because a man is using a weed whacker, does not necessarily mean he is trimming his hedges.
exists e1 e2 s1 x1 x2 x3 x4.(Theme(e2,x4) & Actor(e2,x1) & v_use(e2) & n_whacker(x4) & a_weed(s1) & Theme(s1,x4) & n_gear(x1) & of(x1,x3) & n_safety(x3) & Actor(e1,x1) & v_wear(e1) & of(x1,x2) & n_man(x2))
exists e1 x1 x2.(n_hedge(x2) & of(x2,x1) & n_male(x1) & n_man(x1) & Theme(e1,x2) & Actor(e1,x1) & v_trim(e1))