数词,介词

数词

[思维导图]

数词属于高考试题中不常考查的冷点，主要涉及基数词和序数词的基本用法及区别，序数词前的修饰词以及分数的正确表达等。

一、基数词

1.常用基数词表

2.基数词构成歌诀

1至12逐个记，13至19 teen结尾。

20至90整十位，ty结尾是后缀。

要是表示“几十几”，连字符十位连个位。

若要表示“几百几”，hundred之后and立。

若要用于复合形容词，连字符相连不加-s。

注意：(1)hundred，thousand，million，billion等词前有基数词或several时，须用单数；与of连用时，用复数，但其前面不能再加数词。如：

six hundred people h undreds of people

(2)dozen前有具体数词修饰时，用单数，of可省略；当dozen后面接these，those，them，us等词时，须先接of，再接这些词，但dozen仍不加-s；dozens of中的of不可省。score用法和dozen相当，但of一般不省略。

several dozen pencils dozens of students

three dozen of these eggs two dozen of them

two score of eggs scores of books

3.基数词的位置

常位于another，all之后，such，more之前，可置于last，next，other之前或之后。

another two days all the ten books

one more apple two such pens

his last two days/his two last days

4．用以表示年龄时，逢十的基数词复数之前应加形容词性物主代词。

in her forties在她四十多岁时

二、序数词

常用序数词表

注意：21以上的多位数词，只将末位数变为序数词，前面的其他位数仍用基数词。如：

21st→twenty-first；22nd→twenty-second；33rd→thirty-third；100th→one hundredth

1．序数词前一般要加上定冠词或形容词性物主代词等限定词。

It was the/my first visit to Europe.

那是我第一次去欧洲。

2．分数的分母部分用序数词，分子为1时，分母用序数词的单数形式；分母为2及以上时，分母用序数词的复数形式。

1/3one－third2/3two－thirds

数词的应用

1.用于构成分数、百分数、小数

one third

two thirds/two-thirds

two-fifths of the students

thirty percent of the water

six point four

注意：表示几分之几(或百分之几)的人或物时，须在分数(或百分数)和人或物之间加of。若充当主语，谓语动词的数应与of后面的名词的数保持一致。如：Seventy percent of her income was spent on clothes.

2.倍数表达法

(1)A＋谓语＋倍数＋as＋原级＋as＋B

The bag is twice as big as that one.

(2)A＋谓语＋倍数＋as many/much＋名词＋as＋B

I have twice as many books as he (does).

(3)A＋谓语＋倍数＋比较级＋than＋B

This classroom is three times bigger than ours.

(4)A＋谓语＋倍数＋the size(width/length/height/depth等)＋of＋B Your piece of bread is three times the size of mine.

注意：表达倍数时，常用half表示“一半”，用double或twice表示“两倍”，用基数词＋times表示三或三倍以上。

3.日期的表达

(1)某年：in＋数字

in 2018

(2)某月：in＋月份

in May

(3)某年某月：in＋月＋年

in May 2018

(4)某年某月某日：on＋月＋日/on＋日＋月，＋年

on May 1(st)/1(st) May,2018

4.时刻的表达

twenty-one past/after eight或eight twenty-one

four to/of nine或eight fifty-six

half past eight或eight thirty

a quarter to/of ten或nine forty-five

5.年代的表达

the early 1920s/1920’s

the early twenties

the mid-eighties

6.其他特殊表达

(1)表示“每一段时间”或“每隔……”every three days/every fourth day

every other day

every few days

(2)表示年龄

in one’s teens

in one’s twenties

at the age of 17

He is twenty years old.

He is a man of twenty.

He is a twenty-year-old man.

(3)用于习语中

one at a time one by one ten out of ten