An old man in green is walking down a broad sidewalk.
An old man falls down the stairs
The old man cannot be walking down a broad sidewalk and fall down the stairs simultaneously.
exists e1 s1 s2 s3 x1 x2 x3.(a_down(s3) & Manner(e1,s3) & Theme(e1,x3) & Actor(e1,x1) & v_walk(e1) & n_sidewalk(x3) & a_broad(s2) & Theme(s2,x3) & in(x1,x2) & n_green(x2) & n_man(x1) & a_old(s1) & Theme(s1,x1))
exists e1 s1 x1 x2.(n_stair(x2) & down(e1,x2) & Actor(e1,x1) & v_fall(e1) & n_man(x1) & a_old(s1) & Theme(s1,x1))