倍数 Multiple | 玄数

2015-05-16

选一选

 The new stadium being built for the next Asian Games will be _____ the present one.

A. as three times big as B. three times as big as
C. as big as three times D. as big three times as
Answer

一、倍数 Multiple

英语的倍数一般表示为:(1)A是B的X倍; (2)增加原来的X倍、减少原来的1/X ,意味着包含基数,是最后结果。或者增加 X  倍 、减少1 / X ,不包括基数,是纯增加。

倍数的表示方法 : 基数词 + times / fold 或 用百分比 “ %” 表示

2倍 : twice ,double , as … agian as ;
3倍 :thiple , three times ;
4倍 :quadruple , four times

二、A是B的X倍

1.  X times as + 形容词 / 副词原级 + as

Jack runs three times as fast as Jim. …………… 杰克跑步是吉姆的三倍那么快。

2.  X times + 形容词 / 副词比较级 + than

A is twice longer than B.  …………… A比B长两倍。
A is twice less than B.  …………… A是B的1/2。

3.  X times + the length(width ,height,size ,value)of

The earth is 49 times the size of the moon.  …………… 地球是月球的49倍大。

4.  as much(many)again as  是 … 的1倍;half as much(many)as   是 … 的半倍;half as much(many)again as   是 … 的1倍半

The dress is not half as beautiful as that one. …………… 这条裙子还没那条的一半好看。

三、倍数的增减

by表示 增加 / 减少了多少,而to表示增加 / 减少至多少

reduce by 1/5 —— 减少1/5
reduce to 1/5 —— 减少 1/5

1.  increase(speed up ,step up ,go up ,raise ,rise ,grow)+ by + 倍数 / 百分数

The sell of computer go up by three times over the last year.
电脑的销售量比去年高了三倍。

2.  decrease(drop ,fall ,weaken ,reduce ,speed down ,step down ,go down) + by + 倍数 / 百分数

The price of computer has droped by 1/3……………. 电脑的价格下降了1/3。

3.  increase(rise ,decrease ,reduce)+ to

练习. A is four times ________ B.

A. as long as B. so long as C. long as D. longer as
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