The man is playing a guitar.
There is a grandfather playing an electric guitar.
We have no idea if that man is a grandfather, and not all guitars are electric.
exists e1 x1 x2.(n_man(x1) & Theme(e1,x2) & Actor(e1,x1) & v_play(e1) & n_guitar(x2))
exists p1 x1 e1 s1 x2 x3 x4.((x1 = x2) & Theme(e1,x4) & Actor(e1,x3) & v_play(e1) & n_guitar(x4) & a_electric(s1) & Theme(s1,x4) & (x2 = x3) & n_grandfather(x2))