People wearing black, some with face masks, are singing.
The people are creepy.
The people could have been wearing funny masks instead of creepy masks.
exists e1 e2 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 s1 x1.(n_people(x1) & Theme(s1,x1) & a_creepy(s1))