第1个回答 2009-03-26
first-第1
second-2
third-3
fourth-4
fifth-5
sixth-6
seventh-7
eighth-8
ninth-9
tenth-10
eleventh-11
twelfth-12
thirteenth-13
fourteenth-14
fifteenth-15
sixteenth-16
seventeenth-17
eighteenth-18
nineteenth-19
twentieth-20
一般来说只要在基数词后加”th”，遇10倍的数要去”y”变”i”加”eth”，只要记一些特殊的，例如第1，第2，第3，第9，第50．．．
如果像第21，要这样改写：twenty-first!希望你能懂！
第2个回答 推荐于2017-11-27
one— first
two— second
three— third
four-fourth
five— fifth
six— sixth
seven— seventh
eight—eighth
nine—ninth
ten— tenth
eleven— eleventh
twelve— twelfth
thirteen 十三
fourteen 十四
fifteen 十五
sixteen 十六
seventeen 十七
eighteen 十八
nineteen 十九
twentieth本回答被提问者采纳
第3个回答 2012-06-25
one— first
two— second
three— third
four-fourth
five— fifth
six— sixth
seven— seventh
eight—eighth
nine—ninth
ten— tenth
eleven— eleventh
twelve— twelfth
thirteen 十三
fourteen 十四
fifteen 十五
sixteen 十六
seventeen 十七
eighteen 十八
nineteen 十九
twentieth
第4个回答 2013-04-04
我教你一法：
1、2、3变字体，
th从4上起。
8加h、9减e。
用f代ve，
ty变为tie。
回答：
one→ first
two→ second
three→third
four→fourth
five→ fifth
six→ sixth
seven→seventh
eight→eighth
nine→ninth
ten→tenth
eleven→eleventh
twelve→ twelfth
thirteen→thirteenth
fourteen→fourteenth
fifteen→fifteenth
sixteen→sixteenth
seventeen→seventeenth
eighteen→eighteenth
nineteen→nineteenth
twenty→twentieth
第5个回答 2009-03-26
1 one
2 two
3 three
4 four
5 five
6 six
7 seven
8 eight
9 nine
10 ten
11 eleven
12 twelve
13 thirteen
14 fourteen
15 fifteen
16 sixteen
17 seventeen
18 eighteen
19 nineteen
20 twenty
参考资料：百度知道