科技英语写作数词和介词PPT课件

1、2021-11-171Contents1Numerals2Prepositions第1页/共54页2021-11-172Numeralsp The introduction of numeralsp The expression of fractional numeralsp The usage of numerals第2页/共54页2021-11-173The introduction of numerals 所谓数词，包括我们常见的基数词，序数词，时间，年代等，除此之外，本节我们要给大家介绍一下科技英语中分数和倍数的表示方法以及数词的一些用法。 第3页/共54页2021-11-174The

2、 expression of fractional numerals1、一般表达法的公式为：分子（用基数词）/分母（用序数词，分子超过1时要用复数）例如：三分之一 one third九分之八 eight ninths四分之三 three quarters/three fourths注意：二分之一，英美人习惯用a half 或者one half, 而不用one second.第4页/共54页2021-11-175The expression of fractional numerals2、用于表示“零点几（十分之几）”、“零点零几（百分之几）”等比较小且数值不确定时的公式为：e.g. 零点几（即

3、：十分之几） a few tenths零点零几（百分之几） a few hundredths零点零零几（千分之几） a few thousandths分子（a few/ several) /分母(tenths, hundredths, thousandths等）第5页/共54页2021-11-176The expression of fractional numerals注意：如果分数后有单位，则要用如下公式：分数表示法+of a/an +单位（单数形式）例如：这药丸重零点零几克。This pill weighs a few hundredths of a gram.只要使VBE变化零点零几伏

4、，就可以使基极电流发生明显的变化。By varying VBE only a few hundredths of a volt, the base current can be changed significantly.第6页/共54页2021-11-177The expression of fractional numerals3、用于表示“千分之.”，“万分之.”，“百万分之.”等比较小的且数值确定的公式有以下两种：（1）基数词 + parts(基数词为1时用单数）/ per (= in a)+数词 或 in +阿拉伯数字例如：百万分之七 seven parts in a million

5、 (per million) 或者 seven parts in 108千分之三 three parts per thousand (=in a thousand) 或者 three parts in 103第7页/共54页2021-11-178The expression of fractional numerals（2）a/an +序数词 +part /per (=in a ) + 数词 或 in + 阿拉伯数字例如：百万分之三 a third part in 106 或 a third part in a million 千分之七 a seventh part in 103 或 a se

6、venth part in a thousand第8页/共54页2021-11-179The usage of numerals1.数词在句子中作前置修饰语（即数词修饰名词）时的句型 倍数 the + 名词 + that + 后置定语（多为of短语） 分数 what从句例如： 月球的体积约为地球的1/4。The moon is about one quarter the size of the earth.不久的将来，对这种设备的需求量将为目前的20倍。The demand for this kind of equipment in the near future will be 20 tim

7、es what it was.铝的导电率为铜的1.6倍。The conductivity of aluminum is 1.6 times that of copper.第9页/共54页2021-11-1710The usage of numerals2.表示倍数增长的句型（1） n times +比较级 = n times as 原级 as注意：在用英语表达“*比*增长了*倍”时，英语需在汉语的基础上增加一倍。例如：这只箱子比那只重5倍。This box is six times heavier than that one.这句话还可以译成“这只箱子重是那只箱子的6倍”。质子的重量为电子的1

8、840倍。 A proton is 1840 times heavier than an electron.这句话还可以译为 “质子的重量比电子重1839倍”。这个电压时加给放大器的信号的80倍。This voltage is 80 times the signal applied to the amplifier.第10页/共54页2021-11-1711The usage of numerals2.表示倍数增长的句型(2) increase by n times 增加了n 倍 increase n times increase n fold 增加到n倍；增加了（n-1）倍 increase

9、 by a factor of n e.g. In this case, both the pulse spacing and the group length are increased 8 times.在这种情况下，脉冲间隔及脉冲组长度均增加了七倍。In this case, both the pulse spacing and the group length are increased by 8 times.在这种情况下，脉冲间隔及脉冲组长度均增加了八倍。第11页/共54页2021-11-1712将下列的句子译成英语，注意正确的使用数词。1.1.该电路中的电流为电源的短路电流的一半。2

10、.2.这种蓄电池的内阻仅为零点零零几欧姆。3.3.其误差为6/10126/1012。4.4.这台计算机储存的信息比那台多3 3倍。5.5.月球的质量为地球的1/811/81。6.6.不久的将来对这种设备的需求量将为现在的2020倍。7.7.这个元件上的电压为零点几伏特。8.8.现在其内部的压力是原来的1/31/3。Exercise第12页/共54页2021-11-1713Exercise1.The current in the circuit is one half the short-circuit of the source.2.The internal resistance of thi

11、s kind of storage battery is only a few thousandths of an ohm.3.Its error is six parts in 1012.4.This computer stores four times more information thanthat one does.5.The mass of the moon is 1/81 that of the earth.6.The demand for this kind of equipment in the near future will be 20 times what it is.

12、7.The voltage across this component is a few tenths of a volt.8.Now its internal pressure is one third what it was.第13页/共54页2021-11-1714Prepositionsp Ofp Withp Byp Forp Onp Inp Over第14页/共54页2021-11-1715Of1. of + 某些抽象名词=adj，但语气更强。本书将有助于计算机专家了解最新的技术。This book will be of great help in exposing computer

13、 scientists to the latest technology.此测量非常精确。This measurement is of great precision.观察电现象非常有趣。It is of great interest to observe electrical phenomena.第15页/共54页2021-11-1716Of2. of表示“在.之中”，其后要接可数名词复数。所有这些仪表中，这一台最贵。Of all these instruments, this one is the most expensive.在新增加的三章中，第一章论述脉冲和数据通讯，第二章讲解雷达，第

14、三章介绍电视。Of these three new chapters, the first treats pulse and data communications, the next covers radar, and the last one introduces television.第16页/共54页2021-11-1717Of3. of表示前后两者处于同位关系。化学这门科学在当今世界非常有用。The science of chemistry id very useful in the modern world.电位差这一概念将在下一节介绍。The concept of potenti

15、al difference will be introduced in the next section.第17页/共54页2021-11-1718Of4. of后面的名词其前面名词（来自于不及物动词）的逻辑主语或者逻辑宾语。物体对净力F的反应就是正比于F的加速度a。The response of a body to a net force F is an acceleration a proportional to F.我们用椭圆来描述行星绕太阳运行的情况。Ellipses are used to describe the motions of the planets around the

16、sun.我们都很熟悉把速度定义为距离与时间之比。The definition of speed as the ratio of distance to time is familiar to all of us.应避免人体接触有潜在毒性的物质。Expose of the body to potentially toxic substances should be avoided.第18页/共54页2021-11-1719Of5. 在ability，tendency等名词后引出一种特殊的“不定是复合结构”作后置定语。各种物质的导热能力差异很大。These are wide differences

17、 in the ability of various substances to conduct heat.万有引力就是所有物体相互吸引的趋势。Gravity id the tendency of all objects to attract, and be attracted by , each other.第19页/共54页2021-11-1720With1.with + 某些抽象名词等效于与这些名词所对应的副词，但语气更强。这些实验应仔细的做。These experiments should be done with care.这个参数可以精确地加以测量。This parameter c

18、an be measured with accuracy.with rapidity = rapidly第20页/共54页2021-11-1721With2. with与vary, change, increase, decrease等动词连用时可表示“随着”之意。船速随着水的阻力的增大而减小。The boats speed decreases with the increase in water resistance.半导体的导电率随着温度的变化而变化。The conductivity of a semiconductor varies with temperature.第21页/共54页2

19、021-11-1722With3. with位于句首时可表示“对了；有了；在.情况下”等意思。对于交流电来说，情况就不同了。With the alternating current, things are different.有了雷达，我们可以看到远方的物体。With radar, we can see distant objects.第22页/共54页2021-11-1723With4. 表示“用”，其后一般跟具体名词。功率可以用瓦特计来测量。Power can be measured with a wattmeter.我们能够用这种磁铁来制作电铃。We can make an electr

20、ic bell with this kind of magnet.第23页/共54页2021-11-1724With5. 表示“具有，带有”（此时介词短语一般只能做后置定语）这是具有两个变量的函数。This is a function with two variables.波长各不相同的无线电波以相同的速度传播。The radio waves with different wavelengths travel at the same speed.第24页/共54页2021-11-1725With6. 构成“with 结构”，在句中作状语和后置定语。由于存在阻力，一部分功率以热能形式被损掉了。W

21、ith resistance present, a part of power had been lost as heat.圆心在远点，半径为a的圆的方程为x2+y2=a2。The equation to the circle with its center at the origin and of radius a is x2+y2=a2.注意：“with 结构”的构成 participle phrase * prepositional phrase *with + n + adj phrase * adv phrase infinitive phrase n phrase第25页/共54页

22、2021-11-1726By1. 表示除了时间和距离外的任何参数的数值。这时压力增加了9倍。At this point, the pressure has increased by a factor of 10.在这种情况下，这两个矢量相位相差30。In this case, the tow vectors differ in phase by 30.第26页/共54页2021-11-1727By2. 表示“根据，按照”，用于推导之中。按照胡克定律便可以求出该力。By Hookes law, one can find out the force.根据式（3），我们可以得到下面这个表达式。By

23、Eq.(3), we can obtain the following expression.第27页/共54页2021-11-1728By3. by + 动名词或表示动作的名词表示“通过.”之意。通过分析该设备的参数，我们就能了解它的特点。By analyzing the parameters of the device, we can understand its features.通过考察此模型，人们便能了解原子的结构。By an examination of this model, one can learn about the structure of an atom.第28页/共5

24、4页2021-11-1729By4. 在method前用by，表示“用.方法”。我们可以用这种方法来克服困难。We can overcome the difficulty by this method.这是克服这个缺点的唯一的方法。This is the only method by which the disadvantage may be overcome.第29页/共54页2021-11-1730By5. 表示尺寸“长，宽，高”相乘的含义。那个实验室是一间4*12米的房间。That laboratory is a room 4 by 12 m.这个设备的尺寸是12*18*6英寸。This

25、 device measures 12 by 18 by 6 inches.第30页/共54页2021-11-1731For1. 表示时间或距离的长短几年来他们一直在研究这种计算机。They have been working for several years on such a computer.输出可保持高电位很长时间。The output may stay high for a long time.第31页/共54页2021-11-1732For2. 表示条件，意为“对于；当.时候；如果.”的话。如果x1,则该式不成立。For x1, this equation does not ho

26、ld.这本书对于初学者来说太难了。This book is too difficult for a beginner.第32页/共54页2021-11-1733For3. 与动词solve连用表示方程所要求解的对象。在这种情况下，要解方程（2-1）以求出未知数。In this case, Eq.(2-1) will be solved for the unknown.我们必须解这个方程求x。It is necessary for us to solve this equation for x.第33页/共54页2021-11-1734For4. 在method ,technique, algo

27、rithm, condition, requirement, name等词后多用for。解决这个问题的方法有很多种。The methods for solving this problem are many.本文介绍了一种在描述图论中某些工程问题求解的算法语言。This paper presents an algorithm for describing the solution of some engineering problems in the graph theory.第34页/共54页2021-11-1735For5. 表示“为了；供；用于”等含义。这些解决方案仅供参考。These

28、solutions are for reference only.这是一本电气工程师手册。This is a manual for electrical engineers.第35页/共54页2021-11-1736For6. 表示“由于”之意。由于此原因，法拉第未能计算出电磁波的传播速度。For this reason, Faraday was unable to calculate the velocity of the propagation of electromagnetic waves.第36页/共54页2021-11-1737For7. 引出不定式复合结构的逻辑主语。太阳光达到地

29、球需要大约8分钟的时间。It takes about 8 minutes for sunlight to reach the earth.这货物太重，那台起重机吊不起来。This cargo is too heavy for that crane to lift.第37页/共54页2021-11-1738On1. 在其之后跟有动名词或表示动作的名词时，一般表示“一.就；在.之后”之意，此时也可用upon。物质一经挤压其体积就会缩小。On being compressed, a substance will be reduced in volume.整理上述方程，我们得到下列方程组。Upon r

30、earranging the above equations, we obtain the following set of equations.第38页/共54页2021-11-1739On2. 表示“对于；论及；关于”。温度对压力的影响应该考虑进去。The influence of temperature on/upon pressure should be taken into account.这些是有关该材料机械性能的资料。These are the information on the mechanical properties of the material.第39页/共54页20

31、21-11-1740On3. 表示“在.时”。在第二个半周时，Q1截止而Q2导通。On the second half cycle, Q1 is off while Q2 is on.可以通过考察在输入电压两个交变半周期间的电流来描述这个电路的工作情况。The operation of this circuit may be described by tracing the current on alternate half-cycles of the input voltage.第40页/共54页2021-11-1741In1. in 后跟表示单位的名词复数（hertz除外）时，表示“用”。

32、这里t的度量单位为秒。Here t is measured in seconds.电感是用亨利作单位来度量的。Inductance is measured in henries (或henrys）.注意：在equation, relation, expressions等后以“in +变量”出现时，也表示用的意思。They represent two relations in these two unknowns.第41页/共54页2021-11-1742In2. in后跟表示方向的词时，意为“朝”。声波是朝四面八方传播的。Sound waves travel in all directions

33、.直流电只能朝一个方向流动。Direct current flows only in one direction.第42页/共54页2021-11-1743In3. in可表示“方面”。这是英美人的习惯用法。两个状态的压力、体积和温度相差一定的量。States 1 and 2 differ in pressure, volume, and temperature by a definite amount.这些练习的难度很不相同。The exercises vary considerably in difficulty.这些设备的体积各不相同。These devices differ great

34、ly in size.第43页/共54页2021-11-1744In4. in后跟动名词或表示动作的名词时，意为“在.时候；在.过程中；在.方面”。我们在讨论微分方程的时候，应把注意力集中在一次方程上。In our discussion of differential equations, we shall restrict our attention to equations of the first degree.由于难于产生均匀的薄膜，所以不可能精确的控制电阻值。Because of the difficulty in producing uniform films, it is not

35、 possible to control values precisely.第44页/共54页2021-11-1745In5. 在reduction, decrease, increase, change, drop, rise, fall等表示变化的名词后多用in。这样会引起温度的下降。This causes a decrease in temperature.在对流层，温度随着高度的增加而持续下降。In the troposphere, there is a steady fall in temperature with increasing altitude.第45页/共54页2021-

36、11-1746In6. 表示“比”的含义。这条线的斜率为1：9。This line has a slope of 1 in 9.用这种方式抽出两张相连的洪涛的概率为1/17。There is a 1-in-17 chance of drawing two successive hearts in this manner.第46页/共54页2021-11-1747Over1. 表示“通过；越过”（其后常为表示距离的名词、其前常为表示移动的动词或名词）这个气球能飞跃100公里。This balloon can fly over 100 kilometers.将它输送到远方会损耗掉一些能量。Its

37、transmission over a long distance causes some losses of energy.第47页/共54页2021-11-1748Over2. 表示“与.相比”（通常在advantage等词后）这种新的方法与原来相比有许多优点。This new method has many advantages over the original one.这个温度与前面提到的150相比有了明显的下降。This temperature is a marked decrease over the150 previously cited. 第48页/共54页2021-11-1749Over3. 表示“在.范围内”。我们很容易确定该汽车在这段距离上的平均速度。It is easy for us to determine the cars average velocity