Two people strolling behind a school bus.
Two people are outside.
School buses are outside, so to be behind a school bus, one must also be outside.
exists e1 x1 x2 x3 x4.(a_topic(x1) & behind(e1,x3) & n_bus(x3) & of(x3,x4) & n_school(x4) & Actor(e1,x2) & v_stroll(e1) & (x1 = x2) & n_people(x1) & card_eq_2(x1))
exists s1 x1.(Theme(s1,x1) & a_outside(s1) & n_people(x1) & card_eq_2(x1))