Group of people dance with smiles at their faces.
Some men are happy at a concert.
Not everyone smiles when he is happy; not everyone is happy when he smiles. Dancing occurs everywhere, not just at a concert.
exists s1 x1 x2 x3 x4.(ne_org_group(s1) & a_topic(s1) & of(s1,x1) & with(x1,x3) & at(x3,x4) & n_face(x4) & of(x4,x1) & n_thing(x1) & n_smile(x3) & Time(x1,x2) & n_dance(x2) & n_people(x1))
exists s1 x1 x2.(at(s1,x2) & n_concert(x2) & Theme(s1,x1) & a_happy(s1) & n_man(x1))