A mid sized mixed gender choir sings while the director motions to keep beat.
There is a mixed gender choir.
A mixed gender choir is there, regardless of any additional details.
(-x)
exists p1 x1 s1 x2 x3.((x1 = x2) & n_choir(x2) & of(x2,x3) & n_gender(x3) & a_mixed(s1) & Theme(s1,x2))