A black-haired man plays a guitar.
The man is a great guitarist.
We don't know that the man is great.
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 p1 x1.(n_man(x1) & exists s1 x2.((x1 = x2) & n_guitarist(x2) & a_great(s1) & Theme(s1,x2)))