**数词:基数词与序数词测试**

**一、选择题**

1. 基数词“十五”对应的英文是:

   A. fifteen B. fiveteen C. five ten D. five and ten  

   **答案:A. fifteen**

2. 以下哪个基数词在变为序数词时需要将"y"改为"ie"再加"th"?

   A. twenty B. thirty C. forty D. ninety  

   **答案:C. forty**

3. 99的英文表示为:

   A. ninety nine B. ninety and nine C. ninety-nine D. ninety nineth  

   **答案:C. ninety-nine**

4. 下列哪个基数词的序数词形式是不规则变化的?

   A. six B. eight C. twelve D. nine  

   **答案:C. twelve**

5. 750,000,000,000用英文表示为:

   A. seven hundred and fifty billion B. seven hundred fifty billion

   C. seven hundred and fifty millions D. seven hundred fifty millions of billions  

   **答案:A. seven hundred and fifty billion**

**二、填空题**

6. 34的英文基数词表示为______,序数词表示为______。

   答案:thirty-four, thirty-fourth

7. 67的英文基数词表示为______,序数词表示为______。

   答案:sixty-seven, sixty-seventh

8. 803的英文基数词表示为______,序数词表示为______。

   答案:eight hundred and three, eight hundred third

9. 1,001的英文基数词表示为______,序数词表示为______。

   答案:one thousand and one, one thousandth first

10. 18,423的英文基数词表示为______,序数词表示为______。

    答案:eighteen thousand, four hundred and twenty-three, eighteen thousand, four hundred and twenty-third

**三、翻译题**

11. 将基数词"thirty-five"转换为序数词。

    答案:thirty-fifth

12. 将基数词"ninety-nine"转换为序数词。

    答案:ninety-ninth

13. 将基数词"two hundred and seventy-six"转换为序数词。

    答案:two hundred and seventy-sixth

14. 将基数词"seven thousand, five hundred and sixty-two"转换为序数词。

    答案:seven thousand, five hundred and sixty-second

15. 将基数词"five billion, two hundred and thirty-four million"转换为序数词。

    答案:five billion, two hundred and thirty-four millionth

**四、简答题**

16. 描述基数词在1-20之间的变化规则。

   答案:基数词在1-20之间的变化遵循固定的顺序,分别为:one, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen, fifteen, sixteen, seventeen, eighteen, nineteen, twenty。

17. 解释基数词在21-99之间的表达方式。

   答案:基数词在21-99之间,先说“几十”,然后加上连字符,再接“几”。例如,23写作twenty-three,34写作thirty-four。

18. 说明基数词在101-999的表示方法。

   答案:基数词在101-999中,先说“几百”,然后用“and”连接,最后加上末两位数。例如,586写作five hundred and eighty-six。

19. 描述1,000以上的基数词如何表达。

   答案:1,000以上的基数词从右向左数,每三位加一个逗号,第一个逗号前为thousand,第二个逗号前为million,第三个逗号前为billion。例如,750,000,000,000写作seven hundred and fifty billion。

20. 写出基数词转为序数词的基本规律,并列举几个不规则变化的例子。

   答案:基数词转为序数词的基本规律是在词尾加上“th”,但有以下不规则变化:one变成first,two变成second,three变成third,five变成fifth,eight变成eighth,nine变成ninth,twelve变成twelfth。以“y”结尾的基数词,如twenty,需将“y”变为“ie”再加“th”。例如,twenty变为twentieth。

**五、应用题**

21. 将基数词“forty-five”转换为序数词,并写出转换过程。

   答案:forty-five → forty-fifth

22. 根据基数词转为序数词的口诀,写出基数词“twenty-four”的序数词形式。

   答案:twenty-four → twenty-fourth

23. 表达基数词“seventy-two”在1,000,000之后的位置。

   答案:seventy-two millionth

24. 将基数词“three hundred and ninety-eight”转换为序数词,并写出转换过程。

   答案:three hundred and ninety-eight → three hundred and ninety-eighth

25. 将基数词“five billion, one hundred and twelve million, three thousand, five hundred and sixty-two”转换为序数词。

   答案:five billion, one hundred and twelve million, three thousand, five hundred and sixty-two → five billion, one hundred and twelve million, three thousand, five hundred and sixty-second

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**答案解析**

1-15题的答案已在题目中给出。16-25题的答案如下:

16. 规则:one, two, three, ..., eighteen, nineteen, twenty。

17. 方法:twenty-one, twenty-two, ..., ninety-nine。

18. 方法:one hundred and one, two hundred and three, ..., nine hundred and ninety-nine。

19. 描述:thousand, million, billion。

20. 规律:词尾+th;不规则:first, second, third, fifth, eighth, ninth, twelfth。

21. 过程:forty-five → forty-fifth

22. 序数词:twenty-fourth

23. 位置:seventy-two millionth

24. 过程:three hundred and ninety-eight → three hundred and ninety-eighth

25. 序数词:five billion, one hundred and twelve million, three thousand, five hundred and sixty-second