A person lies at the bottom of a flight of stairs.
The person fell down the stairs.
Not all persons fell down the stairs.
exists e1 x1 x2 x3 x4.(n_bottom(x2) & at(e1,x2) & of(x2,x3) & of(x3,x4) & n_stair(x4) & n_flight(x3) & Actor(e1,x1) & v_lie(e1) & n_person(x1))
exists e1 s1 x1 x2.(n_stair(x2) & n_person(x1) & a_down(s1) & Manner(e1,s1) & Theme(e1,x2) & Actor(e1,x1) & v_fall(e1))