悬挂着的导线下端放在一个小型马蹄形磁铁的两个磁极之间。
We can stop this trouble if we use a special rod.
如果我们用某种特制的杆，就能解决这个问题。
Some typical fabrication methods are shown in Fig.11-36.
若干种典型的组装方法如图11-36 所示。
 
翻译的基本方法 – 增词与减词 Skills of Translation –adding and reducing words
    在应当表示名词的复数概念时，要根据上下文判断其复数是“二”还是“几个”。要善于选择适当的量词。
Metals can be classified as pure metals and alloys.
金属可分为纯金属与合金两类。
Since its formation the earth has been undergoing changes.
地球自形成以来，一直经历着各种变化。
Chromium improves the properties of steel.
铬可改进钢的各种性能。
The air is made up of mixture of gases.
空气是由多种气体混合而成的气体。
We saw bubbles rising from under the water.
我们看到一个个水泡从水下升起。
The frequency, wave length and speed of sound are closely related.       
频率、波长与声速三者密切相关。
 
翻译的基本方法 – 增词与减词 Skills of Translation –adding and reducing words
4. 补充句子成分：英译汉时，有时所有的词汇都相应地译出后，汉语句子的结构显得不完整。这时，应补充缺少的句子成分。
It has long been known that electricity is a form of energy.
我们早就知道电是能的一种形式。（补充主语）
An exact solution demands much calculation.
一个精确的解答要求进行很多次计算。（补充谓语）
When the wire stops moving, the current stops.
当导线停止移动时，则电流就停止流动。（补充宾语）
Fuses are cheap, other equipment is much more expensive.
保险丝很便宜，但其它保险设备却昂贵得多。 （补充定语）
Why do satellites stay in orbit? Why don’t they shoot off intoouter space? 
为什么卫星会留在轨道上运行？它们为什么不会飞出轨道而进入外层空间呢？（补充状语）
 
翻译的基本方法 – 增词与减词 Skills of Translation –adding and reducing words
5. 补充解释性词语：
    当按照英语句子逐词翻译不能清楚、明确表达原句概念时，可补充解释性词语进行解释说明。
The following discussion assumes the teeth to be perfectly formed, perfectly smooth, and absolutely rigid.
下面的讨论中假定轮齿加工没有误差， 轮齿表面完全光滑， 轮齿为绝对刚体。
You can also purify water by boiling it and condensing the steam which you have collected.
你也可把水煮沸,将收集到的蒸汽凝结,用这样的方法来提取纯水。
The angle β shown in the figure is the angle between plane PQ and a horizontal plane.
图中所示的β角为PQ 平面和水平面之间的夹角
 
翻译的基本方法 – 增词与减词 Skills of Translation –adding and reducing words
6. 补充语气连贯性词语：
The reliability of semiconductor devices is very important, especially in space applications.
半导体器件的可靠性至关重要, 特别是在空间技术应用中尤其如此。
Take the case of the hydrogen atom. It has only one electron in the shell. How many electrons more are needed to complete this shell? The answer is one.
以氢原子为例，它的壳层中仅有一个电子，还需要加几个电子来补满这个壳层呢？回答是：还需要一个。
 
翻译的基本方法 – 增词与减词 Skills of Translation –adding and reducing words
（二）减词译法
    有时在英语句子必不可少的词，在汉语中有时是可有可无，甚至是多余的。这时，汉译时必须省译。英语中的介词、连接词、代词、冠词等在汉译时也常常省译。
Now that we are all here, we begin to make our experiment at once.
直译：既然我们都到齐了，我们立刻开始我们的实验。
正译：都到齐了，我们立刻开始做实验吧。
If the wire has small cross section, the electric current which flows through it per second will be small in quantity.
直译：如果导线的截面积小，每秒钟通过导线的电流在数量方面将是小的。
正译：导线的截面积小，每秒钟所流过的电流就小。
 
翻译的基本方法 – 增词与减词 Skills of Translation –adding and reducing words
1. 省译从修辞角度看不必重复的词
Steel contains a smaller proportion of carbon than cast iron contains.
钢的含碳率比铸铁小。(第二个contains 系重复词)
Matter is constantly changing and is constantly moving.
物质在不断地变化和运动着。
2. 省译逻辑上不必要的说明语
The present process of making steel from iron in only about 100 years old.
目前的炼钢法只有约100年的历史。（不必译出“由铁炼钢的方法”）
Domestic lighting circuits should be at least two in number.
家用照明电路至少应该是两条。 （不必译出“在数量上是两条”）
 
翻译的基本方法 – 增词与减词 Skills of Translation –adding and reducing words
3. 省译修辞上所不需要的词
Copper is a material which has the property of elasticity.
铜是一种具有弹性的材料。(省译property因为“弹性”已表明“性质”
To start a car moving, work must be done on it.
要开动汽车，就必须对它做功。(不必译为“开动汽车运动”)
There are two kinds of materials used in engineering.
工程材料有两种。（不必译为“工程中所使用的材料”“工程材料”自
然是“使用在工程中”的。）
A generator can not produce energy, what it does is to convert mechanical energy into electrical energy.
发电机不能产生能量,它只是把机械能变为电能. (省译“它所做的事”)
 
机械工程专业英语文献阅读之四  Fasteners and Springs 2
Springs are mechanical members which are designed to give a relatively large amount of elastic deflection under the action of an externally applied load. Hooke's Law, which states that deflection is proportional to load, is the basis of behavior of springs. However, some springs are designed to produce a nonlinear relationship between load and deflection. 
The following is a list of the important purposes and applications of springs:
 
机械工程专业英语文献阅读之四  Words Learning
spring  1. 普通词义:春天, 泉，2. 专业词义：弹簧,弹性,弹力,发条
Spring begins in March.   春天从三月开始。
There is a hot spring in the village.  
村子里有一口温泉。
Please adjust the spring on the equipment to increase the axial 
spring applied on the axle.
请调节一下设备上的弹簧，使作用在轴上的弹力增加。
elastic deflection  弹性变形
When a force is applied on a spring, elastic deflection will appear.  当对弹簧加力时，弹簧就会发生弹性变形。
We can make a light signal deflect to another direction by a Prism.    我们可以用一个棱镜使光信号偏转一个角度。
 
机械工程专业英语文献阅读之四  Words Learning
state 陈述, 说明,  状况，国家
The relationship between mass and energy in  nature is stated briefly in this article. 
本文简述了自然界中质量与能量的关系。
Every body continues in its state of rest unless it is compelled to change that state by forces applied on it.
每一个物体保持其静止状态,除非有加于其上的力,它才会改变那种状态。
state universities 国立大学；
critical state  临界状态；
existing state 现状；  finished state 成品形状；
 
机械工程专业英语文献阅读之四  Words Learning
nonlinear relationship  非线性的，非直线的
The output voltage and input current  in this circuit is a nonlinear relationship. 
这个电路的输出电压与输入电流是一种非线性关系。
The deformation of a metal bar on a elongation test machine and the force on it is nonlinear relationship after its elastic deformation.
在拉伸试验机上拉伸金属棒,在弹性变形之后其变形量与所加的力成非线性关系。 
be linear with  与……成线性关系
Deformation of a spring is linear with the force applied on it.
弹簧的变形量与施加在其上的作用力成线性关系。
 
机械工程专业英语文献阅读之四  Fasteners and Springs 2
(1) Control of motion in machines. This category represents the majority of spring applications such as operating forces in clutches and brakes. Also, springs are used to maintain contact between two members such as a cam and its follower.
(2) Reduction of transmitted forces as a result of impact or shock loading. Applications here include automotive suspension system springs and bumper springs.
(3) Storage of energy. Applications in this category are found in clocks, movie cameras and lawn mowers. Many parking meters use spring mechanisms which perform the timing function.
(4) Measurement of force. Scales used to weigh people is a very common application for this category.
 
机械工程专业英语文献阅读之四  Words Learning
category  种类，类别，范畴
Works place all machined parts in category so that the installation of the production line will be more efficiency.
工人们把加工好的机器零部件分门别类的放好以便提高生产线的安装效率。
represents  表现，表示，描写
The basic concepts of laser technology and data collected are represented in this paper.
本文给出了激光技术的基本概念和收集的数据。
maintain  维持，坚持，维修，保养
He bring enough food to maintain life and leave for forest. 
他带够了足够维持生命的食物然后向森林出发了。
Engineers maintain all machines once a year.
机械师每年将全部设备维修一次。
 
机械工程专业英语文献阅读之四  Words Learning
storage  贮藏， 存储器
A storage is such a device that can retain data.