The football players are working on stretching their legs.
The football players are preparing for the big game.
Stretching their legs does not mean they are preparing for the game
exists e2 e1 x1 x2 x3 x4.(n_leg(x4) & of(x4,x1) & n_thing(x1) & n_player(x1) & of(x1,x2) & n_football(x2) & on(e1,e2) & Theme(e2,x4) & Actor(e2,x3) & v_stretch(e2) & Actor(e1,x1) & v_work(e1))
exists e1 s1 x1 x2 x3.(n_game(x3) & a_big(s1) & Theme(s1,x3) & n_player(x1) & of(x1,x2) & n_football(x2) & for(e1,x3) & Actor(e1,x1) & v_prepare(e1))