People are waling past a wall that is covered in advertisements.
The wall is blank.
A wall that is covered in advertisements is not blank.
exists e1 e2 x1 x2 x3 x4.(past(e1,x2) & in(e2,x4) & n_advertisement(x4) & Theme(e2,x3) & v_cover(e2) & (x2 = x3) & n_wall(x2) & Actor(e1,x1) & v_wale(e1) & n_people(x1))
exists s1 x1.(n_wall(x1) & Theme(s1,x1) & a_blank(s1))