Couples are dancing on the street
Couples are doing the samba.
Just because a couple are dancing does not mean they are doing the samba.
exists e1 x1 x2.(n_street(x2) & on(e1,x2) & Actor(e1,x1) & v_dance(e1) & n_couple(x1))
exists e1 x1 x2.(n_samba(x2) & Theme(e1,x2) & Actor(e1,x1) & v_do(e1) & n_couple(x1))