数词

第二讲数词

一、基数词

1. 1-12是独立单词

13-19是以-teen结尾的单词

20-90这八个十位数词以后以-ty结尾 写出1-20,30,40,50，…，90

2. 其他两位数词，十位数与个位数之间需用连字符

twenty-three, seventy-five, ninety-two

3. 百位数与十位数之间，英式英语用and连接，美式英语一般不用 3,456 three thousand four hundred (and) fifty-six 4. million 1,000,000

billion 1,000,000,000

trillion 1,000,000,000,000

5. 指精确数字时候, ten, hundred, thousand,million只用单数形式，不加s six hundred students

表示“成百上千，成千上万，许许多多”，基数词要加s

hundreds of soldiers thousands of birds 6. dozen(12)

dozen同基数词或several, many 等词连用时或，要用单数形式，而表示不确定的数字时候，要用复数形式，常用结构为 dozens of+复数名词 two dozen bottles of beers dozens of times 比较:

Some dozens of children are playing over there. Some dozen (of) children are playing over there.

7. 数词常与名词连用，构成复合定语，中间要用连字符，而且只用名词的单数形式

A three-hundred-word abstract 摘要 二、序数词

1. 序数词除了前三个(first, second, third)形式特殊以外，其余序数词都以-th结尾，例如

fourth, sixth, tenth，但是fifth, ninth, twelfth拼写有变化。

2. 以-ty结尾的基数词如何变序数词

以-ty结尾的基数词变序数词时候，将-y改为-i再加-eth。例如thirtieth。 3. 两位数的基数词变序数词

twenty-one -> twenty-first, sixty-five -> sixty-fifth

三、倍数表示法

1. “增加了„„倍”，不包括基数，即纯增加。若说“增加到„„倍”或“是原来的„„

倍”，则包括基数

1

The machine improves the working condition and raise efficiency four times. 提高了三倍，提高到四倍

Production costs have dropped four times. 降低了3/4，降低到1/4. 2. 两倍，三倍，等表示法

两倍常用twice, double表示，3倍用three times, triple, treble, threefold表示；四倍用quadruple，或者基数词+times表示。 You are twice of her age It is worth twice the value.

They have produced five times as many washers as they did last year. 3. 倍数比较表示法

(1) X times + as + 形容词或副词原级 + as

Room A is twice as wide as Room B. Jack runs three times as fast as Jim.

(2) X times + 形容词或副词比较级 + than

A is three times longer than B. A比B长2倍；A是B的三倍长。

The car runs twenty percent faster than the motor.

The cotton output was four times greater than that of 1996. A is twice less than B.

(3) X times + the width/ length/ breadth/ level/ value/ size/ velocity of

The earth is 49 times the size of the moon. The earth is 49 times as large as the moon. (4) (half) as much/ many/ large again as知道即可

half as many/ much as 是半倍

half as many/much again as 是一倍半

as many/ much again as 是两倍 I have half as many books as she has.

Mary has half as much money again as John. I have as much wine again as you.

4. 倍数增减表示法

reduce by 2/3 reduce to 2/3

增加了X-1倍，增加到X倍，增加了百分之：

(1) Increase/ speed up/ rise/ grow up + by + 百分数或者倍数 The output of steel went up by three times over the previous year. (2) Increase/ be/ rise/ grow/ multiply/ go up + 数词 + times

The production of notebook computers has been increased six times as compared with 2002.

(3) Multiply X times 和multiplied by

表示增加了X-1倍

The production has multiplied eight times.

(4) increase/ exceed/ go up/ rise/ reduce/ decrease… +/ by a factor of + 数词

increase by a factor of 8 增加了7倍 reduce by a factor of 5 减少了4/5

2

The speed exceeds the average speed by a factor of 4.

四、概数表示法

(1) over, above, more than + 数字

over two years above twenty pounds more than 90 degrees

(2) below, under, less than + 数字

below six days under two hours

(3) about, around , nearly, some, approximately + 数字

数字+名词+ or so;

数字+名词+more or less

About a hundred other students failed in the exam. They had to wait an hour or so for the police to arrive. 五、“每隔”、“每逢”表示法

两种结构，意义相同 every + 基数词 + 复数名词 every + 序数词 + 单数名词 每四天，每隔三天 every four days

every fourth day

翻译 every three lines every tenth meter 六、比例表示法

One in eight jointed the club.

Of the twenty students, fifteens are girls.

七、次数提问与回答

总次数

A : How many times have you seen her? B : I have seen her three times. 间隔次数

A : How often do you see her? B: I see her once a month. 八、half用法

(1) 表示一半

half a

half the a half

a half of

He ran half a mile. John earns half her salary.

(2) and a half 又一半

She studied abroad for two years and a half.

练习题(二)

1. We are to study ____ this week.

A. Four Chapter B. Chapter Fourth C. Chapter Four 2. He met the old man ___ times on the way back.

3

D. Fourth Chapter

A. dozen of B. dozen C. dozens D. dozens of 3. She’d like to drive ____.

A. car twenty-first B. car twenty-one C． car the twenty-one D. twenty-one car 4. She told me that she was then living in a ______.

A. two-stories wooden house B. wooden two-story house C two-story wooden house D. wooden house two storied 5. There are five ____ on the team.

A.seven-feet over tall players B.over seen-foot-tall players

C.over seven-feet-tallplayers D.seven-foot tall over players 6. The Chicago bus is parked at ____

A. Lane two B. the lane two C. the two lane D. lane the two 7. “Did you buy anything at the clothing store?”

“Yes, I brought three ____ ties for just twelve dollars. “

A. five-dollar B. fives-dollar C. five-dollars D. fives-dollars

8. There are two ways to make these machines, but ____ is worth of note. A. A first B. one C. the one D. the first 9. There are ten on the list, so you are ___.

A. A eleventh B. the eleventh C. an eleven D. eleven 10. There were _____ of spectators at the demonstration.

A. thousand B. thousand’s C. a thousand D. thousands 11. She was a good-looking woman in ____.

A. forties B. the forties C. forty D. the forty

4