A man and a woman are singing into microphones.
The man and woman are on a concert stage.
You can not infer there is a concert.
exists e1 x1 x2 x3 x4.(into(e1,x4) & n_microphone(x4) & Actor(e1,x1) & v_sing(e1) & subset_of(x3,x1) & n_woman(x3) & subset_of(x2,x1) & n_man(x2))
exists p1 x1 x2 x3.(n_woman(x3) & n_man(x2) & subset_of(x3,x1) & subset_of(x2,x1) & exists x4 x5.(on(x1,x4) & n_stage(x4) & of(x4,x5) & n_concert(x5)))