一、 序数词的定义 表示顺序的数词叫做序数词，是由基数词变化而来的。 二、序数词变化规律 1、2、3，单独记，(one—first, two—second, three—third) th要从4加起， 8少t，9去e，(eight—eighth, nine—ninth) ve用f来代替，(five—fifth, twelve—twelfth) y用ie来代替，(twenty—twentieth, thirty—thirtieth) 几十几和几百几，只变个位记心里。(twenty-one—twenty-first ) 思考：hundred（百）的序数词是什么？ 一、写出下列数字的序数词 One— eleven— twenty-one— Two— twelve— twenty-two— twenty— Three— thirteen— twenty-three— thirty— Four— fourteen— twenty-four— forty— Five— fifteen— twenty-five— fifty— Six— sixteen— twenty-six— sixty— Seven— seventeen— twenty-seven— seventy— Eight— eighteen— twenty-eight— eighty— Nine— nineteen— twenty-nine— ninety— Ten— hundred— 二、 扩展 January, February, March, April, May, June, July, September, October, November, December 1. Christmas Day (圣诞节)is _________. 2. Labor’s Day (劳动节)is ______. 3. New Year’s Day (元旦)is ________. 4. April Fool’s Day (愚人节)is ________. 5. Tree Planting Day (植树节)is ____________. 6. Children’s Day (儿童节) is _____ 7.Teachers’ Day (教师节) is ___________. 本文来源：https://www.wddqw.com/doc/799d3065dd36a32d73758162.html