基数词 序数词one firsttwo secondthree thirdfour fourthfive fifthsix sixthseven seventheight eighthnine ninthten tentheleven eleventhtwelve twelfththirteen thirteenthfourteen fourteenthfifteen fifteenthsixteen sixteenthseventeen seventeentheighteen eighteenthnineteen nineteenthtwenty twentiethtwenty-one twenty-firsttwenty-two twenty-secondtwenty-three twenty-thirdthirty thirtieth注：first ( 1st ) second ( 2nd ) third ( 3rd )
