三、序数词
序数词表示事物的顺序，往往与定冠词the连用。常用的序数词如下：

序数词	缩写	序数词	缩写
first second third fourth fifth sixth seventh eighth ninth tenth   eleventh   twelfth	1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th 12th	twentieth twenty-first thirtieth thirty-fifth fortieth fiftieth sixtieth seventieth eightieth ninetieth hundredth	20th 21st 30th 35th 40th 50th 60th 70th 80th 90th 100th

四、数词的某些用法
1. 表示计量
表示事物的计量，即事物的长度、宽度、深度和高度，应采用基数词。如：
It is 50 metres/kilometers/miles long (wide, deep, high).
它有50米/千米/英里长（宽、深、高）。
2. 表示编号
编号的数字如果过小，可用序数词或基数词表示；如果数字较大，通常用基数词表示。如：
The tenth lesson=Lesson Ten    第10课
Room 405                   第405号房          
Page 215                    第215页
No.14 Middle School          第14中学
Telephone NO.5855806         电话： 5855806
3. 表示不确切的数字
基数词后面直接加上复数名词表示精确的数字，而基数词复数形式加上“of” 表示不确切的数字。如：
five hundred students           500名学生
two thousand people            2000人
five dozen pencils              5打铅笔
hundreds of students            几百名学生
millions of workers             成千上万的工人
scores of chairs                几十张椅子
4. 表示年龄和岁数
1）表示年龄的主要句式如下：
He is a boy of 10 yeas old.                    他是个10岁的男孩子。
He is 10 yeas old.                           他10 岁。
At the age of ten, he began to learn English.      他10岁开始学英语。
He is 10(years of age).                       他10 岁。
He is a the-year-old boy.                      他是个10岁的男孩子。
2) 介词in+ one’s twenties (thirties…) 表示 “在某人20多岁（30多岁……）”。如：
My father is in his fifties.        我爹50多岁。
When he was in his forties, he began to learn English.    当他40多岁时，他开始学英语。
5.表示年代
表示什么世纪，什么年代时，通常在数词后加s或’s，并在年代前加定冠词the ,如1980’s
（20世纪80年代），读作：nineteen eighties. 如：
     His grandfather died in the 1970’s。           他爷爷死于20世纪70年代。
6. 表示分数
分数的表达方式是：分子用基数词，分母用叙述词。分子是one时，分母不必加s; 分子大于one时，分母要加s.如：
a(=one) third    三分之一            one fifth     五分之一
two thirds       三分之二            three fourths     四分之三
Two thirds of the trees were cut down the years ago.
10年前三分之二的树木被砍伐了。 

7. 表示百分数
百分数的表达方式是：基数词+ percent（单数形式）+of+名词。如：
Thirty percent of the students in my class are from cities.    我班30%的学生来自城市。
About 61 percent of the surface is covered by water.    大约61%的表面被水覆盖着。

强化练习题
1. I sent invitations to 90 people, ____ have replied.
A. of whom only 30 of them                B. of whom only 30
C. only 30 of those who                     D. only 30 who
2. When the bell rang announcing the end of class, students came out ____.
A. by twos and threes                B. by two and three
C. by two or three                      D. by twos or threes
3. Li Ping was born ____.
A. in the year 1984, at 10 a.m. on June 18th
B. on June 18th at 10 a.m. in the year 1984
C. at 10 a.m. in the year 1984 on June 18th
D. at 10 a.m. on June 18th in the year 1984
4. David helps his mother with the housework every Saturday for about____.
A. one and half hours                    B. a half and an hour
C. an hour and half                      D. one and a half hours
5. This is a ____building, which is about ____ high.
A. six-storey; 38 metre                  B. six-storeys; 38-metre
C. six-storeyed; 38 metres               D. six-storey; 38-metres

6. The cotton production has increased by ____ percent this year compared with last year.
A. five point six eight    
B. five point sixty-eight  
C. fifth point and six eight  
D. five point and six eight
7. — What would you like, sir?
    — ____, please.
A. Two cups of teas                   B. Two teas  
C. Two cup of tea                       D. Two cups tea
8. The airport is ____ from my hometown.
A. two hour's ride                      B. two hours' ride
C. two hour ride                        D. two hours ride
9. ____ people have come to realize the importance of learning English. Now they go to various sorts of schools to take up English courses of one kind or another.
A. Hundred and thousand 
B. One hundred and thousand of
C. A large amount of  
D. Hundreds of thousands of

10. She was so ill because of overwork that she had to leave her work half-done to ask for ____.
 A. a three day sick leave
 B. three-days sick leaves
 C. a sick leave of three days  
 D. three-day sick leaves
11. A library with five thousand books____ to the nation as a gift.
A. is offered           B. has offered          C. are offered           D. have offered
12. The hero of the story is an artist in his____.
A. thirtieth            B. thirty               C. thirty’s              D. thirties
13. Shortly after the accident, two _____police were sent to the spot to keep order.
A. dozen of           B. dozens              C. dozen               D. dozens of
14. There are____ visitors in the exhibition every day.
A. hundred           B. hundreds of           C. hundreds            D. a hundred of
15. About ____ the people of the town are workers.
A. sixty percent                              B. sixty percent of        
C. percent sixty                              D. sixty percents of
16. He came to China in ____. 
A. forty            B. forties            C. late forties           D. his early forties
17. The story happened ____.
A. in 1960’s        B. in his 60’s         C. in 60’s              D. in the 1960’s
18. About ____ of these rooms ____ empty.
A. two third, are     B. two thirds, are      C. two thirds, is         D. two third, is
19. ---- When is your birthday party?
   ---- It’s on Friday,____ .
A. fifth October                         B. five October        
C. the fifth of October                    D. the five of October  
20. I _____ met him in Guilin in 1996.
A. the first          B. the firstly          C. first                D. first time
21. Tom and I went to the cinema but we weren’t able to get tickets for ___.
A. two of us                           B. the two of us
C. the second of us                      D. second of us
22. He worked well and was praised ____ in public.
A. a second time     B. twice time         C. the second time        D. for a second time
23. The ____ paragraphs want rewriting.
A. one fifth         B. first one           C. first four             D. two-thirds
24. Mary was the____ of the ____ students climbed up to the top of the hill.
A. nine, fourty      B. nineth, fortieth       C. ninth, forty          D. nine, fortieth
25. ____ people have visited the _____ stone bridge.
A. Two millions of, 500-foot-long
B. Several millions of, 500-feet-long
C. Two million, 500-feet-long
D. Millions of, 500-foot –long

26. Staying in a hotel for a day costs____ renting a house in the country for a week.
A. twice more than
B. twice as much as
C. as much as twice
D. as much twice as
27.----I understand you have a relative visiting you?
----Yes, my____ grandmother.
A. ninety-year-olds
B. ninety-old-year
C. ninety-years-old
D. ninety-year-old.
28. The Yangtze River is___ the Pearl River.
A. three times long as
B. three times as long as
C. as three times longer as
D. as long three times as

答案与解析（部分）
1. 答案是B.名词/代词+of +关系代词(which/whom)常引导非限制性定语从句,of whom only 30 =only 30 of whom。
2. 答案是A. by/in twos and threes 意为“三三两两地”,是固定短语。
3. 答案是D.英语表达时间的顺序是由小到大。

4. 答案是D.一个半小时应表达为:an hour and a half或one and a half hours。
5. 答案是C.第一空“六层的楼房”可表达为a six-storey building/ a six-storied building/ a building of six stories; 第二空“数词+名词+形容词”作表语时,名词常用其复数形式,使用连字符构成复合形容词时,只可用作前置定语,如:a 38-meter-high building。
6. 答案是A. 5.68的英文表达为five point six eight。 
7. 答案是B. tea/coffee有时可作可数名词,表示“一杯茶或咖啡”。two teas = two cups of tea。
8. 答案是B. “数词+ hours'/minutes' + ride/drive/walk”为习惯表达。
9. 答案是D.
10. 答案是C.
11.答案是A. 主要考查数词与主谓一致的关系。句中with five thousand books 是主语，用来修饰 library, 因此句子的主语是library,而不是books.
12. 答案是D. in +one’s+基数词的复数形式，表示 “某人××多岁”。注意：in+ the+ 基数词的复数形式，表示某一世纪的××年代。
13. 答案是C. A项的形式不对（应在dozen后加s）;数词与dozen连用时，dozen不应加s,
故B项不对；dozens of 的形式是对的，但不能与数词连用，故D项也不对。这样，ABD3项都被排除了。
14. 答案是B。表示一个模糊的数字应是：hundreds of +可数名词复数。
15. 答案是B. 表示百分数的方式是：percent(单数形式)+of+名词。
16. 答案是D. 表示 “岁数”的方式是：介词in +one’s twenties(thirties…)。
17. 答案是D. 表示年代时，在具体年代之前必须加定冠词。
18. 答案是B.表示分数时，如果基数词大于one，序数词后必须加s，因此A和D两项应先排除。根据主谓一致的原则，句中的谓语动词应用复数形式。

19. 答案是C. 日期应用序数词表示,前面有定冠词the.
20. 答案是C. first 在此处用作副词,所以不能加定冠词.
21.答案是B.  two of us 表示 “我们中的两人”,  the two of us  表示 “表示两人”.
22. 答案是A. a加序数词表示 “再” “又”,相当于another.
23. 答案是C. 既然paragraphs是复数,就排除了A和B,而D的two-thirds后要加of才能接复数名词.    
24.答案是C. 本题主要考查个别拼写特殊的基数词和序数词.
25. 答案是D. 在millions of前不能再出现数量词, 所以可先排除A,B,而C的复合形容词中间应用单数名词,又如: a five-year-old boy.
26.答案是B. 本题主要考查倍数与as much(many)as的词序.
27.D 28.B.