A group of men and women are singing a song.
A group of carolers sing Christmas tunes.
Just because they are singing does not mean they are carolers singing Christmas tunes.
exists e1 x1 x2 x3 x4 x5.(Theme(e1,x5) & Actor(e1,x1) & v_sing(e1) & n_song(x5) & of(x1,x2) & n_woman(x4) & n_man(x3) & subset_of(x4,x2) & subset_of(x3,x2) & n_group(x1))
exists e1 x1 x2 x3 x4.(Theme(e1,x3) & Actor(e1,x1) & v_sing(e1) & n_tune(x3) & (x3 = x4) & ne_tim_christmas(x4) & of(x1,x2) & n_caroler(x2) & n_group(x1))