A person falls through the air in a room, with a step ladder in it.
A person stands up.
One cannot be falling while he/she stands up.
exists e1 x1 x2 x3 x4 x5.(n_thing(x2) & n_air(x2) & with(e1,x4) & in(x4,x2) & Time(x4,x5) & n_ladder(x5) & n_step(x4) & in(e1,x3) & n_room(x3) & through(e1,x2) & Actor(e1,x1) & v_fall(e1) & n_person(x1))
exists e1 s1 x1.(a_up(s1) & Manner(e1,s1) & Actor(e1,x1) & v_stand(e1) & n_person(x1))