A man plays a keyboard and sings.
A boy skips down the street.
A man isn't a boy and when they sings they don't skips.
exists e1 x1 x2 x3 x4.(Theme(e1,x2) & Actor(e1,x1) & v_play(e1) & n_sing(x4) & n_keyboard(x3) & subset_of(x4,x2) & subset_of(x3,x2) & n_man(x1))
exists e1 x1 x2.(n_street(x2) & down(e1,x2) & Actor(e1,x1) & v_skip(e1) & n_boy(x1))