An Asian woman, and a black male, walking past the stairs to the subway.
There are people on a bus.
One cannot be walking on a bus.
exists e1 s1 s2 s3 x1 x2 x3 x4 x5.(n_subway(x5) & n_stair(x4) & a_topic(s1) & to(e1,x5) & past(e1,x4) & Actor(e1,x3) & v_walk(e1) & (s1 = x3) & subset_of(x2,s1) & n_male(x2) & a_black(s3) & Theme(s3,x2) & subset_of(x1,s1) & n_woman(x1) & a_asian(s2) & Theme(s2,x1))
exists p1 x1 x2 x3.((x1 = x2) & on(x2,x3) & n_bus(x3) & n_people(x2))