英语中 1-31 的序数词分别是:1)第1-第10:first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth2)第11-第20:eleventh, twelfth, thirteenth, fourteenth, fifteenth, sixteenth, seventeenth, eighteenth, nineteenth, twentieth3)第21-第30:twenty-first, twenty-second, twenty-third, twenty-fourth, twenty-fifth, twenty-sixth, twenty-seventh, twenty-eighth, twenty-ninth, thirtieth4)第31:thirty-first英语中序数词的变化规律记忆口诀如下:1)1、2、3,单独记,(one—first, two—second, three—third)2)th要从4加起3)8少t,9去e,(eight—eighth, nine—ninth)4)ve用f来代替,(five—fifth, twelve—twelfth)5)y用ie来代替,(twenty—twentieth, thirty—thirtieth) 6)几十几和几百几,只变个位记心里。(twenty-one—twenty-first )