A man in a black shirt plays guitar hero, while another man sits and watches.
A man in a black shirt plays in the final round of the Guitar Hero competition while his friend watches.
Just because you're playing guitar hero with a friend doesn't imply being at a Guitar Hero competition.
exists e1 p1 s1 x1 x2 x3 x4 x6.(exists e3 e2 x5 x7.(Actor(e3,x7) & v_watch(e3) & n_man(x7) & -(x7 = x6) & Actor(e2,x5) & v_sit(e2) & n_man(x5) & -(x5 = x1)) & n_man(x6) & n_man(x1) & n_man(x1) & while(e1,p1) & Theme(e1,x3) & Actor(e1,x1) & v_play(e1) & n_hero(x3) & of(x3,x4) & n_guitar(x4) & in(x1,x2) & n_shirt(x2) & a_black(s1) & Theme(s1,x2))
(x)