1 基数词one 序数first
2.two基数/second
3.three/thrid
4.four /fourth
5.five/fifth
6.six/sixth
7.seven/sevendth
8.eight/eighth
9.nine/ninth
10ten/ tenth
11.eleven /eleventh
12 twelve/twelfth
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 基数/twenty-first序数
看懂了么以次类推了基数在前面,后面是序数的表示 这是我从自己以前回答的问题中复制过来的,你参考下