(defun dms()
  (interactive)
  (let ()
    (beginning-of-buffer)
    (replace-string "iso-8859-1" "GB2312")
    (beginning-of-buffer)
    (replace-string "’" "'")
    (beginning-of-buffer)
    (replace-string "‘" "'")
    (beginning-of-buffer)
    (replace-string "—" "--")
    (set-buffer-file-coding-system 'gb2312)))