数词 知识点
一、数词的定义与分类：数词是指表示数目多少或顺序先后的词。表示数目多少的数词叫基数词，如 one, five, ten, thirty, sixty-five 等；表示顺序先后的数词叫序数词，如 first, sixth, tenth, twenty-first 等。数词用法相当于名词和形容词，在句中可用作主语、宾语、表语、定语、同位语等。
二、基数词：
1. 英语中没有“万”这个读数单位，要表示汉语中的“万”，英语需借用thousand一词，如“一万”用“十个千”表示(ten thousand)，“十万”用“一百个千”表示(one hundred thousand)。
2. 用作基数词单位的 hundred, thousand, million, billion 通常不带复数词尾-s，但若用于表示数百、数千、数百万这样的泛指，则用复数。如：About two thousand people died in the earthquake. 大约有两千人在地震中丧生。
3. 表示整十的基数词用复数形式可以表示人的大约岁数或年代。如：He is in his early twenties. 他才二十出头。
三、序数词
1. 许多序数词是由相应的基数词后加词尾-th构成的，如four / fourth，six / sixth，ten / tenth，sixteen / sixteenth，但是nine变为序数词是ninth，而不是nineth。
2. twentieth, thirtieth, fortieth 等表示整十的序数词，由相应的基数词将词尾y改为ie，再加-th 构成。
3. first, second, third 通常可缩写为1st, 2nd, 3rd。凡是以th结尾的序数词可缩写为“基数词+th”：4th, 5th, 9th, 11th, 60th, 128th等。
4. 非整十的多位数，将个位数变成序数词即可：twenty-first(第21)，thirty-sixth(第36)，ninety-ninth(第99)，three hundred and sixty-fifth(第365)等。
5. hundred, thousand, million 等序数词形式为 hundredth, thousandth, millionth 等。
6. 序数词前通常要用定冠词，但表示考试或比赛等的名次时，通常可省略其前的定冠词。如：My room is on the second floor and his on the third. 我的房间在三楼，他的房间在四楼。
注：有时序数词前不用定冠词，而用不定冠词，表示次第在原有基础上的增加。如：We’ll have to do it a second time. 我们得再做一次。序数词前用定冠词和不定冠词的区别在于：定冠词表特指，不定冠词表泛指，有类似another的意思，但比another 的意思更明确。
四、分数、倍数、小数和百分数
1. 分数。分数由基数词和序数词构成：分子用基数词，分母用序数词，当分子超过“1”时，分母用复数。如：two thirds=2/3；three fifths=3/5
注：1/2 通常读作 a [one] half，一般不读作a second；1/4 可读作 a [one] fourth，也可读作 a [one] quarter。
2. 倍数。英语中表示倍数时通常借助half, double, twice, three times等之类的词。如：They're twice the size of chickens. 它们比鸡大一倍。
Their house is about three times as big as ours. 他们的房子大约有我们房子三倍大。
3. 百分数。百分数由基数词和百分号(%)组成，百分号(%)读作 per cent。如：thirty percent=30% 60 percent=60%
数词 知识点题库
We may find that learning a foreign language does not have to be______learning our mother tongue, but can in fact be twice_______．
A . twice as hard as; as easy as
B . as twice hard as; as easy
C . twice as hard as; as easy
D . as twice hard; as easy as
Two ___________ died in the fire.
A . scores of people
B . score of people
C . scores of peoples
D . score of peoples
The newly-built library is ________ the old one.
A . three times the size of
B . the size of three times
C . three times bigger
D . three times as bigger as
—Would you like______cakes?
—No,thanks.
A . other two
B . another two
C . two another
D . the two other
She went to the bookstore and bought three _______________ books.
A . scores of
B . dozen of
C . score of
D . dozens of
According to a new survey, every year about ______ dollars is spent to look after people with illness caused by smoking.
A . 30 millions of
B . 30 million of
C . 30 millions
D . 30 million
—Can you give an example to show how useful a computer is?
—Sure. people get information from it every day.
A . A large number of; plenty of
B . The number of; a lot of
C . Lots of; a lot
D . Many a; a great deal of
Monday is the ______day of the week.
A . second
B . first
C . the first
D . one
—What does the model plane look like?
—Well the wings of the plane are of its body.
A . more than the length twice
B . twice more than the length
C . more than twice the length
D . more twice than the length
This box is ________ that one. Which of the following is wrong?
A . four times so big as
B . four times the size of
C . four times bigger than
D . one fourth as big as
She went to the bookstore and bought ________.
A . dozen books
B . dozens books
C . dozen of books
D . dozens of books
He went to the bookstore and bought _____.
A . score books
B . scores books
C . score of books
D . scores of books
India is a country with ___________people.
A . the number of
B . few
C . a few
D . a number of
—David, how old is your father this year?
—______. And we just had a special party for his _____ birthday last weekend.
A . Fortieth; forty
B . Forty; forty
C . Forty; fortieth
D . Fortieth; fortieth
