A singer performs on stage at a concert.
A man is singing a pop song
A singer that performs on   stage does not mean it is a man and singing does not mean a pop song.
exists e1 x1 x2 x3.(at(e1,x3) & n_concert(x3) & on(e1,x2) & n_stage(x2) & Actor(e1,x1) & v_perform(e1) & n_singer(x1))
exists e1 x1 x2 x3.(Theme(e1,x2) & Actor(e1,x1) & v_sing(e1) & n_song(x2) & of(x2,x3) & n_pop(x3) & n_man(x1))