Doyouknowasayingabouttheswanfeather（天鹅羽毛）？ Thissayi...
问题详情： Doyouknowasayingabouttheswanfeather（天鹅羽毛）？ ThissayingcomesfromahistoricbookcalledLuShi；Accordingtothestory，aTangDynastyofficial（唐朝官员）inYunnanwantedtoshowhisrespecttotheemperor．Hesenta...