A band of four young men plays.
They all play guitar
Just becaust they all play guiatar does not mean they are playing guitar, nor does it define who they all are.
exists e1 s1 x1 x2.(Actor(e1,x1) & v_play(e1) & of(x1,x2) & n_man(x2) & a_young(s1) & Theme(s1,x2) & card_eq_4(x2) & n_band(x1))
exists x2.(n_thing(x2) & all x1.((x1 = x2) -> exists e1 x3.(Theme(e1,x3) & Actor(e1,x1) & v_play(e1) & n_guitar(x3))))