A choir is standing up on a podium singing a song.
A choir are in a singing competition.
the choir is not necessarily in a competition
exists e1 e2 s1 x1 x2 x3.(for(e1,e2) & Theme(e2,x3) & Actor(e2,x1) & v_sing(e2) & n_song(x3) & on(e1,x2) & n_podium(x2) & a_up(s1) & Manner(e1,s1) & Actor(e1,x1) & v_stand(e1) & n_choir(x1))
exists p1 x1.(exists s1 x2.(in(x1,x2) & n_competition(x2) & a_singing(s1) & Theme(s1,x2)) & n_choir(x1))