Seniors enjoy themselves at a dance.
The teenagers were dancing.
Seniors are not teenagers.
exists e1 x1 x2 x3.(n_group(x2) & at(e1,x3) & n_dance(x3) & Theme(e1,x2) & Actor(e1,x1) & v_enjoy(e1) & n_senior(x1))
exists e1 x1.(n_teenager(x1) & Actor(e1,x1) & v_dance(e1))