A hockey player guards the goal.
A hockey player is stopping a fast break.
A hockey player guards the goal does not imply that he is stopping a fast break.
exists e1 x1 x2 x3.(n_goal(x3) & Theme(e1,x3) & Actor(e1,x1) & v_guard(e1) & n_player(x1) & of(x1,x2) & n_hockey(x2))
exists e1 s1 x1 x2 x3.(Theme(e1,x3) & Actor(e1,x1) & v_stop(e1) & n_break(x3) & a_fast(s1) & Theme(s1,x3) & n_player(x1) & of(x1,x2) & n_hockey(x2))