begin
  routine do it
  end
  integer a,b
  do it if not a = b
  comment do it if not a = b
  do it unless not a = b
  comment do it unless not a = b
  if not a = b then do it
  comment if not a = b then do it
  unless not a = b then do it
  comment unless not a = b then do it
endofprogram