基数词
1、1-10的基数词：one. two. three. four. five. six. seven. eight. nine. ten.
2、11-19的基数词: eleven, twelve, thirteen, fourteen, fifteen, sixteen, seventeen, eighteen, nineteen.
3、21-29的基数词：twenty-one, twenty-two, twenty-three, twenty-four, twenty-five, twenty-six, twenty-seven, twenty-eight, twenty-nine.
4、20-90的基数词：twenty, thirty, forty, fifty, sixty, seventy, eighty, ninety.
5、100 基数词 ：hundred.
6、1-10的序数词：first. second. third. fourth. fifth. sixth. seventh. eighth. ninth. tenth.
7、11-19的序数词：eleventh, twelfth, thirteenth, fourteenth, fifteenth, sixteenth, seventeenth, eighteenth, nineteenth.
8、21-29的序数词：twenty-first, twenty-second, twenty-third, twenty-fourth, twenty-fifth, twenty-sixth, twenty-seventh, twenty-eighth, twenty-ninth.
9、20-90的序数词：twentieth, thirtieth, fortieth, fiftieth, sixtieth, seventieth, eightieth, ninetieth.
10、100序数词：hundredth.
基数词1-10变序数词的规则，直接在后面加th 。 但是第一first，第二second，第三third不一样。还要注意第五是把five后面的ve变成f再加th，第八因为尾部已经有一个t, 所以直接加上h 。第九把nine后面的e去掉再加th。
