1=First 1st
2=Second 2nd
3=Third 3rd
4=Fourth 4th
5=Fifth 5th
6=Sixth 6th
7=Seventh 7th
8=Eighth 8th
9=Ninth 9th
10=Tenth 10th
11=Eleventh 11th
12=Twelfth 12th
13=Thirteenth 13th
14=Fourteenth 14th
15=Fifteenth 15th
16=Sixteenth 16th
17=Seventeenth 17th
18=Eighteenth 18th
19=Nighteenth 19th
20=Twentieth 20th
21=Twenty-first 21th
22=Twenty-second 22nd
23=Twenty-third 23rd
24=Twenty-fourth 24th
25=Twenty-fifth 25th
26=Twenty-sixth 26th
27=Twenty-seventh 27th
28=Twenty-eighth 28th
29=Twenty-ninth 29th
30=Thirtieth 30th
31=Thirty-first 31th
32=Thirty-second 32nd
33=Thirty-third 33rd
34=Thirty-fourth 34th
35=Thirty-fifth 35th
36=Thirty-sixth 36 th
37=Thirty-seventh 37th
38=Thirty-eighth 38th
39=Thirty-ninth 39th
40=Fortieth 40th
41=Forty-first 41st
42=Forty-second 42nd
43=Forty-third 43rd
44=Forty-fourth 44th
45=Forty-fifth 45th
46=Forty-sixth 46th
47=Forty-seventh 47th
48=Forty-eighth 48th
49=Forty-ninth 49th
50=Fiftieth 50th
51=Fifty-first 51st
52=Fifty-second 52nd
53=Fifty-third 53rd
54=Fifty-fourth 54th
55=Fifty-fifth 55th
56=Fifty-sixth 56th
57=Fifty-seventh 57th
58=Fifty-eighth 58th
59=Fifty-ninth 59th
60=Sixtieth 60th
61=Sixty-first 61th
62=Sixty-second 62nd
63=Sixty-third 63rd
64=Sixty-fourth 64th
65=Sixty-fifth 65th
66=Sixty-sixth 66th
67=Sixty-seventh 67th
68=Sixty-eighth 68th
69=Sixty-ninth 69th
70=Seventieth 70th
71=Seventy-first 71st
72=Seventy-second 72nd
73=Seventy-third 73rd
74=Seventy-fourth 74th
75=Seventy-fifth 75th
76=Seventy-sixth 76th
77=Seventy-seventh 77th
78=Seventy-eighth 78th
79=Seventy-ninth 79th
80=Eightieth 80th
81=Eighty-first 81st
82=Eighty-second 82nd
83=Eighty-third 83rd
84=Eighty-fourth 84th
85=Eighty-fifth 85th
86=Eighty-sixth 86th
87=Eighty-seventh 87th
88=Eighty-eighth 88th
89=Eighty-ninth 89th
90=Ninetieth 90th
91=Ninety-first 91st
92=Ninety-second 92nd
93=Ninety-third 93rd
94=Ninety-fourth 94th
95=Ninety-fifth 95th
96=Ninety-sixth 96th
97=Ninety-seventh 97th
98=Ninety-eighth 98th
99=Ninety-ninth 99th
100=one hundred 100th
以一结尾的加st，例：first-1st
以二结尾的加nd，例：second-2nd
以三结尾的加rd，例：third-3rd
其他的加th，例：fourth-4th fifth-5th…
1、第一类
first (1st) 第一
second (2nd) 第二
third (3rd) 第三
（在括号里的是缩写形式，均在阿拉伯数字后面加上相应序数词的最后两个字母构成，以下各类与此相同。）这类序数词只有三个，在整个序数词里面是特殊的，就和第一类基数词一样，需要逐个地硬记下来。
2、第二类：
fourth (4th) 第四
fifth (5th) 第五
sixth (6th) 第六
seventh (7th) 第七
eighth (8th) 第八
ninth (9th) 第九
tenth (10th) 第十
eleventh (11th) 第十一
twelfth (12th) 第十二
thirteenth (13th) 第十三
fourteenth (14th) 第十四
fifteenth (15th) 第十五
sixteenth (16th) 第十六
seventeenth (17th) 第十七
eighteenth (18th) 第十八
nineteenth (19th) 第十九
这一类序数词共有十六个。均在相应的基数词后面加上后缀－th构成。要注意其中fifth、eighth、ninth、twelth四个词的拼法。
3、第三类：
twentieth (20th) 第二十
thirtieth (30th) 第三十
fortieth (40th) 第四十
fiftieth (50th) 第五十
sixtieth (60th) 第六十
seventieth (70th) 第七十
eightieth (80th) 第八十
ninetieth (90th) 第九十
这一类全是十位整数的序数词，共八个。它们的构成方法是：先将相应的十位整数的基数词词尾－ty中的y改成i，然后在加上后缀－eth。
4、第四类：
thirty-first (31th) 第三十一
sixty-second (62nd) 第六十二
eighty-seventh (87th) 第八十七
ninety-eighth (98th) 第九十八
这类表示“第几十几”的序数词，跟表示“几十几”的基数词一样简单。在构成方法上均由基数词“几十几”变化而来，十位数不变，仅把个位上的基数词变成序数词就行了。
扩展资料：
序数词在句中可作主语、宾语、定语和表语。
The second is what I really need． 第二个是我真正需要的。（作主语）
He chooses the second． 他挑选了第二个。（作宾语）
We are to carry out the first plan． 我们将执行第一个计划。（作定语）
She is the second in our class．在我们班她是第二名。（作表语）
注：序数词在使用时，通常前面要加定冠词the；但是如果序数词前出现不定冠词a或an时，则表示“再......”，“又......”。
