1、序数词变化规则： 一二三特殊记，词尾各是 tdd； th 四加起，八去 t，九去 e，y 结尾改 ie； ve 结尾变 f，five、twelve 是两兄弟； 若是遇到几十几，只变个位就可以。 1-30 基数词和对应序数词：(抄写 2 遍：书上一遍，练习本上一遍) 1:one first 2:two second 3:three third 4:four-fourth 5:five fifth 6:six sixth 7:seven seventh 8:eight eighth 9:nine ninth 10:ten tenth 11:eleven eleventh 12:twelve twe
2、lfth 13:thirteen thirteenth 14:fourteen fourteenth 15:fifteen fifteenth 16:sixteen sixteenth 17:seventeen seventeenth 18:eighteen eighteenth 19:nineteen nineteenth 20:twenty twentieth 21:twenty-one twenty-first 22:twenty-two twenty-second 23:twenty-three twenty-third 24:twenty-fuor twenty-fourth 25:twenty-five twenty-fifth 26:twenty-six twenty-sixth 27:twenty-seven twenty-seventh 28:twenty-eight twenty-eighth 29:twenty-ninetwenty-ninth 30:thirtythirtieth 31.thirty-onethirty-first
