1、IV 数词一、基数词的用法1、从句子成分上分析，基数词在句中可用作主语、宾语、定语等。如：（1）Four of them went to the factory. 他们中的四个人去了工厂。（主语）（2）I want two. 我要两个。（宾语）（3）There are twelve months in a year. 一年有十二个月（定语）（4）My classmate is eighteen. 我的同学十八岁。（表语）2、表示事物的编号，放在名词之后。如：Today we are going to study Lesson Five. 今天我们要学习第五课。Room 403 403周3、表示
2、时刻。表示时间的读法有两种：顺读法：第一个词表示钟点，第二个词表示分钟。如：7:00 seven oclock 6:05 six five / six o five逆读法：先说分钟，再说钟点，中间用介词。（1）表示“几点过几分”，分钟不超过三十用“分钟数+past+钟点数”表示。如：6:05 five past six 12:30 half past twelve（2）表示“几点差几分”，分钟超过三十用“差数+to+下一钟点数”表示。如：1:45 a quarter to two 7:55 five to eight4、表示年龄。（1）表示年龄可用以下结构：她五岁了。She is five (
3、years old).She is five years of age.She is aged five (years).当年龄制定语时，必须用单数结构。如：He is a sixteen - year - old. 他是个十六岁的男孩。（2）at the age of 表示“在岁的时候”，多用作状语。如：At the age of 30, he realized his dream to be a pilot.在三十岁的时候，他实现了做飞行员的梦想。（3）in + ones+整数的基数词复数形式，表示“在某人几十多岁的时候”。如：My grandmother is in her eighti
4、es. 我祖母八十多岁了。5、用于加、减、乘、除的数字用基数词。One plus two is three. 一加二等于三。Five times two is ten. 五乘以二等于十。6、表示倍数。（1）倍数（分数）+as+形容词（副词）原级+ as。如：I have three times as many as you. 我有你三倍那么多。（2）倍数（分数）+形容词（副词）比较级+ than。如：Asia is three times larger than Europe. 亚洲比欧洲大三倍。（3）倍数（分数）+the size (length, weight等)+of。如：The ear
5、th is 49 times the size of the moon. 地球是月球的49倍大。7、表示年份。 The accident took place in 2006. 这次事故发生在二零零六年。8、表示小数。 18.39可写成eighteen point three eight10、表示年代。如：在80年代 in the eighties 在20世纪70年代 in the 1970s / in the 1970s11、表示百分数。百分数由基数词加percent或per cent构成。如：5% five per cent / percent 0.6% zero point six pe
6、r cent / percent 100% one hundred per cent / percent二、序数词的构成和用法。1、序数词的构成。（1）一般在基数词的词尾加上th, 如：sixth（第六）。（2）基数词以ve结尾改为f，再加th，如：fifth t（第五）；twelfth（第十二）（3）以e结尾的基数词，去掉e，再加th，如：ninth（第九）（4）以ty结尾的基数词，把y改为ie，再加th，如：fortieth（第四十）（5）少数几个有各自独特的形式，如：first (第一); second (第二); third (第三); eighth (第八)。2、从句子成分上分析，序
7、数词在句中可用作主语、宾语、定语、表语。如：（1）The first is better than the second. 第一个比第二个要好。（主语）（2）He preferred the third. 他更喜欢第三个。（宾语）（3）Her husband died in the Second World War.她丈夫在第二次世界大战中死去。（定语）（4）He is always the first to get to school.他总是第一个到学校。（表语）3、表示事物的编号可用序数词，放在名词之前。（基数词也可以用来表示编号，放在名词之后）如：the tenth lesson (Le
8、sson 10) 第十课 The seventh page (Page 7) 第七页4、表示世纪用序数词。 如：在21世纪 in the 21st century5、表示日期用序数词。表示日期要用序数词（或阿拉伯数字，但读时仍需用序数词表达），前面要定冠词the。如：在9月1日 on September the first三、分数的表示法。 表示分数时，分子用基数词，分母用序数词。当分子是1时，可以用one，也可以用a；当分子大于1时，分母的序数词要用复数形式；当分母是2或4时，可以用half或quarter代替。如1/4 one / a fourth 3/5 three fifths 1/2
9、 a half 1/4 a quarter注意：“2/5的书”应表达为two fifths of the books, 而不是two fifths books。四、half的用法1、half + a (an) +名词或a half +名词表示“一半”。如： Half a day / a half day 半天2、“半”的表示方法。如：one and a half hours / an (one) hour and a half 一个半小时 Three seconds and a half / three and a half seconds 三秒半真题操练1. Which room are y
10、ou living in?In _ on the _ floor.A. Room 303; twoB. 303 Room; twoC. Room 303; secondD. 303 Room; second2. What do you think of the new book?There are so many new words in _ chapter (章节). Its a bit hard.A. fifthB. fiveC. the fifth4. Basketball is so popular a game in the world that _ people play it f
11、or fun and exercise.A. million ofB. millions ofC. millionsD. two millions of5. Come and see me in _.With pleasure. Thats what Im expecting.A. two or three daysB. two or three days timeC. two or three days time6. How old is your daughter?_. We had a special party for her _ birthday last week.A. Ninth
12、; ninthB. Nine; nineC. Ninth; nineD. Nine; ninth7. Excuse me, how many students are there in your art club?There are _.A. twelveB. twelfthC. the twelfth8. The _ Olympics will be held in August, 2008 in Beijing, China.A. twenty - ninethB. twenty - ninthC. twenty - nine9. Whats the matter, Kangkang?Oh
13、, I feel sorry to hear more than _ people lost their lives in the earthquake (地震) in Sichuan.A. sixty thousands ofB. sixty thousandC. sixty thousand ofD. thousand of10. Shanghai opened its _ TV channel (频道) that sends programs in foreign languages.Great! I can improve my English over it.A. firstB. a firstC. the first答案：1. C 2. C 3. B 4. B 5. C 6. D 7. A 8. B 9. B 10. A