Several couples dance in a plaza.
The couples are in their forties.
Just because there are couple dancing doesn't mean they are in their forties.
exists s1 x1 x2 x3.(a_topic(x1) & in(x1,x3) & n_plaza(x3) & n_dance(x1) & of(x1,x2) & n_couple(x2) & a_several(s1) & Theme(s1,x1))
exists p1 x1 x2.(n_forty(x2) & of(x2,x1) & n_thing(x1) & n_couple(x1) & in(x1,x2))