People wearing black, some with face masks, are singing.
The people are wearing white.
The people are either wearing black or white.
exists e2 e1 p1 x1 x2 x3 x4 x5.(Actor(e2,x1) & v_sing(e2) & rel(x1,x3) & with(x3,x4) & n_mask(x4) & of(x4,x5) & n_face(x5) & n_thing(x3) & exists s1.(Theme(s1,x2) & a_black(s1)) & Topic(e1,p1) & Actor(e1,x2) & v_wear(e1) & (x1 = x2) & n_people(x1))
exists e1 p1 x1.(n_people(x1) & exists s1.(Theme(s1,x1) & a_white(s1)) & Topic(e1,p1) & Actor(e1,x1) & v_wear(e1))