为什么出现乱码？

Question

procedure TForm1.Button3Click(Sender: TObject);
var
   i:integer;
   tlist:tstringlist;
   exl,aa:variant;
   s:string;
begin
   exl:=createoleobject('excel.application');
   exl.workbooks.add;
   aa:=exl.worksheets.item[1];
   exl.visible:=true;
   tlist:=tstringlist.Create;
   try
      with adoq1 do begin
         sql.Clear;
         sql.Text:='select * from [gz$]';
         open;
         first;
         while not eof do begin
            s:='';
            for i:=0 to fieldcount-1 do begin
               s:=s+fields[i].asstring+#9;
               application.ProcessMessages;
            end;
            tlist.Add(s);
            next;
         end;
      end;
      except
      end;
      Clipboard.AsText:=tlist.Text;
      aa.paste;
end;
汉字单元格全是乱码？