A woman is singing and playing guitar.
The woman is using an acoustic guitar.
The woman is not necessarily using an acoustic guitar.
exists e1 e2 x1 x2 x3 x4.(Theme(e2,x4) & Actor(e2,x3) & v_play(e2) & n_guitar(x4) & n_woman(x3) & Theme(e1,x2) & Actor(e1,x1) & v_sing(e1) & n_guitar(x2) & n_woman(x1))
exists e1 s1 x1 x2.(n_woman(x1) & Theme(e1,x2) & Actor(e1,x1) & v_use(e1) & n_guitar(x2) & a_acoustic(s1) & Theme(s1,x2))