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
21 twenty-one
22 twenty- two
23 twenty- three
24 twenty- four
25 twenty- five
26 twenty- six
27 twenty- seven
28 twenty- eight
29 twenty- nine
30 thirty
31 thirty- one
32 thirty- two
33 thirty- three
34 thirty- four
35 thirty- five
36 thirty- six
37 thirty- seven
38 thirty- eight
39 thirty- nine
40 forty
41 forty- one
42 forty- two
43 forty- three
44 forty- four
45 forty- five
1-12 没有规律,需特殊记忆：
one two three four five six seven eight nine ten eleven twelve
13-19是基于3-9在后边加-teen
thirteen fourteen fifteen sixteen seventeen eighteen nineteen
20：twenty
21-29是20加上1-9的数字
如：thirty
31-39是30加上1-9的数字
依此类推～
20、30、40等这些都是什么什么加-ty
