An adult and a kid walk down a city sidewalk.
Two people are riding a rollercoaster.
People that walk down a city sidewalk could not have been riding a rollercoaster the same time.
exists s1 x1 x2 x3 x4 x5.(a_topic(s1) & subset_of(x2,s1) & down(x2,x4) & n_sidewalk(x4) & of(x4,x5) & n_city(x5) & n_walk(x2) & of(x2,x3) & n_kid(x3) & subset_of(x1,s1) & n_adult(x1))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_ride(e1) & n_rollercoaster(x2) & n_people(x1) & card_eq_2(x1))