Two teenagers interacting with the elder population.
Some middle aged people sit alone.
There are teenagers with a population, not middle aged people who are alone.
exists e1 x1 x2 x3 x4.(n_population(x3) & of(x3,x4) & n_elder(x4) & a_topic(x1) & with(e1,x3) & Actor(e1,x2) & v_interact(e1) & (x1 = x2) & n_teenager(x1) & card_eq_2(x1))
exists e1 e2 s1 s2 x1.(a_alone(s2) & Manner(e2,s2) & Actor(e2,x1) & v_sit(e2) & n_people(x1) & Theme(e1,x1) & v_age(e1) & a_middle(s1) & Theme(s1,x1))