A hockey player guards the goal.
A hockey player sat on the bench.
if you are on the bench you are not in the game guarding the goal
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 x1 x2 x3.(n_bench(x3) & on(e1,x3) & Actor(e1,x1) & v_sit(e1) & n_player(x1) & of(x1,x2) & n_hockey(x2))