數(shù)詞Num.數(shù)詞分為兩種：基數(shù)詞（表示數(shù)目）和序數(shù)詞（表示順序）。

考點(diǎn)一 基數(shù)詞的用法

1. 基數(shù)詞的基本用法用作基數(shù)詞單位的hundred, thousand, million, billion 通常不帶復(fù)數(shù)詞尾-s，但若用于表示數(shù)百、數(shù)千、數(shù)百萬這樣的泛指，則用復(fù)數(shù)。

About two thousand people died in the earthquake.

大約有兩千人在地震中喪生。

Thousands of people go to the seaside every year.

每年成千上萬的人到海濱去。

2. 表示年齡和年代的用法表示整十的基數(shù)詞用復(fù)數(shù)形式可以表示人的大概歲數(shù)或某個年代。

He is in his early twenties. 他的年紀(jì)在二十出頭。

This story took place in the 1930s.

故事發(fā)生在20世紀(jì)30年代。

考點(diǎn)二序數(shù)詞的用法

1.序數(shù)詞的構(gòu)成大多數(shù)的序數(shù)詞是由基數(shù)詞加-th構(gòu)成，如：seven—seventh, ten—tenth

以-t結(jié)尾的基數(shù)詞只在詞尾加-h，如：eight—eighth

以-ve結(jié)尾的基數(shù)詞改-ve為f再加-th，如：five—fifth, twelve—twelfth

以-y結(jié)尾的基數(shù)詞改-y為-ie再加-th，如：twenty—twentieth, thirty—thirtieth

幾十幾的序數(shù)詞只在個位數(shù)體現(xiàn)，如：twenty-one—twenty-first,thirty-three—thirty-third

特殊的序數(shù)詞：one—first, two—second, three—third, nine—ninth

2. 不定冠詞a與序數(shù)詞連用序數(shù)詞前加冠詞a表示“再一次”。例如：Can I try a second time? 我可以再試一次嗎？

3. 序數(shù)詞用于分?jǐn)?shù)中描述分?jǐn)?shù)時，分子用基數(shù)詞，分母用序數(shù)詞，分子大于1時，分母加s。例如：1/5：one fifth 2/3：two thirds

考點(diǎn)三 倍數(shù)的表達(dá)法

1.A+be動詞/謂語動詞+倍數(shù)+as+形容詞/副詞原級+as+B例句：Women working as housekeepers in the under 35 age group in 2014 were almost twice as many as in 2004.

譯文：2014年35歲以下的女性做保姆的人數(shù)幾乎是2004年的兩倍。

2.A+be動詞/謂語動詞+倍數(shù)+形容詞/副詞比較級+than+B例句：This building is three times higher than that one.

譯文：這座建筑的高度是那座的四倍。（這座建筑比那座高三倍。）

3.A+be動詞+倍數(shù)+the size/height/length/width，etc+of+B例句：This street is four times the length of that one.

譯文：這條街是那條街的四倍長。

4.times as many/much/often/比較級+as+被比對象例句：Young people used the Internet more than three times as often as the general population in 2014.

譯文：在2014年，年輕人上網(wǎng)人數(shù)是一般大眾的3倍多。

5.times+that+of+被比對象例句：In this workshop, the output of July was 4.5 times that of January.

譯文：這個車間7月份的產(chǎn)量是1月份的4.5倍。