A black-haired man plays a guitar.
A man practices the star spangled banner on his guitar.
It's impossible to know that the black-haired man is practicing the star spangled banner.
exists e1 s1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_play(e1) & n_guitar(x2) & n_man(x1) & a_black-haired(s1) & Theme(s1,x1))
exists e1 e2 x1 x2 x3 x4 x5.(n_guitar(x5) & of(x5,x2) & n_male(x2) & n_star(x2) & Theme(e2,x2) & Actor(e2,x1) & v_practice(e2) & on(e1,x5) & Theme(e1,x4) & Actor(e1,x3) & v_spangle(e1) & n_banner(x4) & (x2 = x3) & n_man(x1))