什么是序数词什么是基数词

序数词与基础词是英语中经常用到的词，很多学生弄不清楚它们两个的概念与用法，因此，很容易在考试中丢失分数。

什么是序数词什么是基数词？

基数词是表示数量多少的词，例如one，two，three等。

序数词是表示顺序或序列的词，例如first，second，third等。

基数词和序数词的区别在于，基数词表示的是数量的大小，而序数词表示的是顺序的位置。

例如，我们可以说有三个苹果three apples，但是我们要表示第一个苹果时就需要用到序数词，即the first apple。

基数词的变化规则：

1、1到12要牢记：

one、two、three、four、five、sixseven、eight、nine、ten、eleven、twelve。

2、十几后面要加teen：

thirteen、fourteen、fifteen、sixteen、seventeen、eighteen、nineteen。

3、整十后面ty添：

twenty、thirty、forty、fifty、sixty、seventy、eighty、ninety。

4、几十几中间有连线：

thirty-two、fifty-one、nienty-nine。

5、特殊情况有八个，三个十几，五整十：

thirteen、fifteen、eighteen。

twenty、thirty、forty、fifty、eighty。

序数词的变化规则：

1、一二三，要全变：one—first，two—second，three—third。

这三个词的变化没有什么规律，必须死记下来。除此以外，其余的都是在基数词末尾加上-th，但是加-th时，有些单词有特殊的变化。

2、八去t：eight—eighth。

eight要先去掉末尾的-t然后再加-th，实际上就是直接加-h。

3、九去e：nine—ninth。

nine要去掉末尾的-e，然后再加-th。

4、字母f代-ve：five—fifth， twelve—twelfth。

five和twelve这两个词是以-ve结尾的，需要用f来代替-ve，然后再加-th。

5、-ty变成-tie：twenty—twentieth，thirty—thirtieth，forty—fortieth，fifty—fiftieth，sixty—sixtieth，seventy—seventieth， eighty—eightieth，ninety—ninetieth。

从20到90的整十数，都是以-ty结尾，这时要把ty变成tie，然后再加-th，实际上就是把y变成ie。

序数词的用法总结：

1、序数词前面一般要加“the”：

The first student to come to school is usually Jim.

2、序数词前面有名词所有格、形容词性物主代词时，不再使用“the”：

He is my first English teacher.

Li Lei's second book is old.

3、a /an+序数词+名词：

序数词前也可以使用a或an, 表示的含义是“又一，再一”，常常有语言环境：

They have two children, and next year they will have a third child.

4、比赛或考试的名次前可省略“the”：

He was second in the exam.

5、the +序数词+最高级：序数词之后有形容词和副词时，用最高级：

The long river is the second longest river in China.

He ran the third fastest in his class.

6、分数：

母序子基：即分母用序数词，分子为基数词，分子大于1，分母加－s。

三分之一：one third。

三分之二：two thirds。

部分分数可以使用 half 和 quarter。

四分之一：one fourth=a quarter。

四分之三：three fourths =three quarters。

二分之一：one second=a half。

7、日期：

5月5日

读作：May (the) fifth；the fifth of May

写作：May 5；May 5th；May the fifth；5 May；5th May。

8、固定搭配中的序数词：

起初：at first。

第一次：for the first time。

首先：first of all。

序数词与基数词习题练习：

( )1. Please turn to ______.

A. Page 11 B. the 11 st page

C. page 11 D. page the 11 th

( )2. At night we can see ______ stars in the sky.

A. thousands and thousands of

B. thousand and thousands of

C. a thousand and thousands

D. thousand and thousand

( )3. There are some _____ in our classroom.

A. hundred of books

B. the hundreds of books

C. hundreds of books

D. hundred of book

( )4. I have been to the village _____

A. a hundred time

B. hundred times

C. hundreds of times

D. hundred of times

( )5. There are ____ students in our school.

A. four—hundred and forty—five

B. four hundred and forty—five

C. four hundreds and forty—five

D. four hundred and forty five

( )6. The teacher told me to go over _____ lessons.

A. thirst three

B. the three first

C. three the first

D. the first three

( )7. May is ____ of a year.

A. the fifth months

B. the fifth month

C. the five months

D. the five month

( )8. We live in ______.

A. the twenty-first century

B. the century twenty-one

C. century twenty-one

D. the century twenty-first

( )9. He said he was going to be free in _____

A. one and a half hour

B. one hour and half

C. one and half hours

D. an hour and a half

( )10. ---How many English books are there on the table?

---There is only _____English book on it.

A. a B. an C. one D. the

( )11. Mr Smith stayed in _____ last night.

A. Room 403 B. the Room 403

C. the 403 room D. 403 the room

( )12. The road is _____.

A. two thousand and five hundred metres long

B. two thousands metres long

C. long one thousand five hundred metre

D. a thousand and five hundreds metres long

( )13. He joined the army on _____ of May 1980.

A. 1 st B. the 1 C. first D. the first

( )14. Is Sunday the ____ day of the week?

A. a B. one C. once D. first

( )15. March the _____ is Women’s Day.

A. eighth B. ninth C. tenth D. eight

( )16. September is the _____month of the year.

A. nineth B. ninth

C. nine D. the twelveth

( )17. December the ____ is Christmas.

A. twenty-five B. twenty-fifth

C. twentieth-five D. twenty-five

( )18. Another way of saying Lesson 12 is ______.

A. Lesson ten-two

B. Lesson Ten-second

C. the Twelfth Lesson

D. Twelfth lesson

答案：

1—5. AACCB

6—10. DBADC

11—15. DADDA

16—18. BBC