1．倍数增加（1）A is n times as great（long，much，…）as B.A is n times greater （longer，more，…）than B.A is n times the size （length，amount，…）of B.以上三句都应译为；A的大小（长度，数量，……）是B的n倍[或A比日大（长，多，……）n-1倍]. 例如：This book is three times as long as （three times longer than，three times the length of ）that one，这本书的篇幅是那本书的3倍（即长两倍）。
注：当相比的对象B很明显时，than（as，of）B常被省去。
（2）increase to n timesincrease n times／n-foldincrease by n timesincrease by a factor of n以上四式均应译为：增加到n倍（或：增加n-1倍）。
例如：The production of cars has been increased to three times as compared with last year。
汽车的产量比去年增加了两倍。
The output of chemical fertilizer has been raised five times as against l986．化肥产量比1986年增加了4倍。
The drain voltage has been increased by a factor of four.漏电压增加了3借（即增加到原来的4倍）。
注：在这类句型中increase常被raise，grow，go/step up，multiply等词所替代。
（3）There is a n-fold increase/growth…应译为：增加n-倍（或增至n倍）。
这个句型还有其它一些形式，如：A record high increase in value of four times was reported.据报道,价值破记录地增长了3倍。
（4）double【增加1倍），treble（增加2倍），quadruple（增加3倍）。
例如：The efficiency of the machines has been more than trebled or quadrupled．这些机器的效率已提高了2倍或3倍多。
2、倍数减少（1）A is n times as small （light，slow，…）as B.A is n times smaller （lighter，slower，…）than B.以上两句均应译为：A的大小（重量，速度，……）是B的1/n[或A比B小（轻，慢，……）（n-1）/n]。
例如：The hydrogen atom is near1y l6 times as light as the oxygen atom.氢原子的重量约为氧原子的1/16（即比氧原子约轻15／16）。
This sort of cloth is twice thinner than ordinary paper.这种布比普通纸张要薄一半（即是普通纸厚度的1／2）。
注：当相比的对象B很明显时，than/as B常被省去。
（2）decrease n times／n一folddecrease by n timesdecrease by a factor of n以上三式均译为：减少到1／n[或：减少（n-1）／n]。
decrease常被reduce，shorten，go／slow down等词替代。
例如：Switching time of the new-type is shortened 3 times。
新型号开关时间缩短了1／3（即缩短到2／3）。
The equipment reduced the error probability by a factor of 5.该设备误差概率降低了4/5。
（3）There is a n-fold decrease／reduction…应译为：减至1／n[或：减少（n一1）／n]。
（17）这个句型还有其它一些形式，如：A rapid decrease by a factor of 7 was observed．发现迅速减少到1／7。
The principal advantage of the products is a two-fold reduction in weight；这些产品的主要优点是重量减轻了1／2。
Exercises:Line A is four times the length of line B. 线条A 是线条B 的四倍长。
I have five times the number of Tom’s books. 我有五倍于汤姆的书。
He has three times my money. 他的钱是我的三倍。
The river is ten times the length of the Tamsui River. 这条河的长度是淡水河的十倍。
This street is four times shorter than that one. 这条街道比那条短四倍。
The mother elephant is one hundred times heavier than the baby elephant.这只母象比小象重一百倍。
It is ten times louder than another. 它比另外一个的声音大十倍。
This street is three times wider than that one. 这条街比那条街宽三倍。
I am twice older than he. 我的年纪比他大两倍。
使用more...than 比较级的例句：He earns five times more money than he did ten years ago. 他现在挣的钱比十年前挣的多5 倍。
There are twice more students in our class than in theirs. 我们班的学生人数比他们班多两倍。
比较级也可使用分数、小数等数字。
例如：The box is one-third bigger than that one. 这个盒子比那个盒子大三分之一。
Last year the output value of industry was 59 percent higher than that of 1976. 去年工业产值比1976 年增长了59 ％。
My command of English is not half so good as yours. 我英语掌握得还不及你的一半儿好。
其它表示法(1) 英语中有些词表示特定的倍数，例如：again (一倍), twice, double (两倍), triple (三倍), fourfold (四倍) 等数。
My Aunt is as old again as I am. 我姑姑的年龄比我大一倍。
The top-brand clothes are often sold as double the normal price here. 售价经常比正常的售价高一倍。
The new work procedure tripled the output. 新工艺使产量增加两倍。
The output of grain increased fourfold. 粮食产量增加了三倍。
(2) 使用by, compared with 等Compared with last year，our coal output has increased by three times. 与去年相比，我们的煤产量增长了 3 倍。
(使用by...)英语increase by究竟如何正确译成汉语，存在着两种不同的意见。
一说译成“增长了”；二说译成“增长到”，跟increase to同义。
可以说，坚持第一种意见的人目前为数不少，几乎要占大多数，因为目前国内出版的一些权威刊物在论述这个问题时，多数都是坚持第一种意见是正确的。
例如：①The output increased by over 200 percent．产量增长了两倍多。
②As against last year，our coal output has increased by three times．与去年相比，我们的煤产量增加了3倍。
③Many counties have increased their farm output by 100 percent or more within a short space of time．许多县在短短的一个时期使粮食产量增长了一倍或一倍多。
④Over the past 17 years，Taching has increased its annual output of crude oil by an average of 28 per cent.大庆原油产量在过去17年间平均每年增长28％。
很明显，上述例句都是中国人自己造出来的，究竟能不能符合英美人的表达方法，只有同英美语言的国家出版的刊物中例句相比较，才能鉴定。
①The strength of the attraction，or repulsion，between two electric charges is doubled if the amount of electricity in one 0f the charges is doubled it increases by 2×2=4 times if the distance between the original charges is halved．我们知道，引力(或斥力)和距离的平方成反比，因此距离缩短一半，引力或斥力(increase by 2×2=4 times)增长到四倍，不是增长了四倍。
②When the signal we pick up has increased by 10 times the grain may have been reduced by 8 times，and the loudness will only have gone up 10／8=1.25 times．信号增大到10倍，增益降低到1／8，音量只增大到10／8=1.25倍。