A family is lounging on their porch.
A families porch collapsed
They cannot be lounging on their porch if their porch is collapsed.
exists e1 x1 x2.(on(e1,x2) & n_porch(x2) & of(x2,x1) & n_thing(x1) & Actor(e1,x1) & v_lounge(e1) & n_family(x1))
exists e1 x1 x2.(Actor(e1,x1) & v_collapse(e1) & Time(x1,x2) & n_porch(x2) & n_family(x1))