in the chemical, plastics and allied industries.
This device can mimic photosynthesis to produce usable energy from sunlight. 采用非转换控制，锅炉设备和制冷装置都在运行，全年可同时供暖和制冷。
该网络服务主要向全球从事化学、塑料及相关工业的专业电子商务用户提供更有价值的服务。 这种装置能够模拟光合作用，利用阳光产生可用的能源。 第1节 翻译练习3
The longitudinal axis of the turbine generator is perpendicular to the axis of the steam generator. In the right conditions, membranes are self-assembling.
Winding of the spring induces residual stresses through bending. 汽轮发电机的纵轴与锅炉轴线垂直。 当条件适宜时，细胞膜会自行聚集。 卷绕弹簧时因为弯曲引起了残余应力。 第1节 翻译练习4
If leakage occurs around output shaft, replace seal and packing.
So they give off a stronger signal to sensitive radiation detectors mounted over the subject’s head. 如输出轴周围漏油，应更换密封件及填料。
因而它向安装在受试者头部上方的灵敏的辐射探测器发出的信号比较强。 第1节 翻译练习5
It is customary to use electromagnets rather than permanent magnets for the field. This flat screen technology eliminates curvature on the screen surface. All the charge on a conductor lies on its surface. 通常磁场用的都是电磁铁而不是永久磁铁。 这种纯平面技术可以消除屏幕表面的弯曲。 导体的全部电荷都在其表面。 6.2 介词短语的译法 第2节 翻译练习1
For ease of assembly and removal of the wheels, the outer races are press-fitted in the wheel hubs. With the length much greater than its width, the coil is called solenoid.
With only about half as many moving parts as a conventional engine, a Wankel is only half the size and weight, and almost completely vibrationless.
为了便于车轮安装和拆卸，把外套圈压入配合到轮毂里。 如果长度远远超过了宽度，这种线圈就称为螺线管。
由于其运动机件数几乎仅为一般发动机的一半，汪克尔发动机只有一般发动机的一半大、一半重，而且几乎完全没有振动。
Without an electric field applied, a dielectric atom is symmetrical.
Despite changes in the load, the voltage applied to it remains fairly constant.
For more information on the improvements we’ve made, scroll down to New Features & Functionality.
如果没有外加电场，电介质原子是对称的。
不管负载如何变化，加在负载上的电压都仍然相当稳定。
要想对我们的改进有更多的了解，请往下看“新特点与新功能”。 第2节 翻译练习2
Singularity functions do not occur in physical systems.
A fair amount of theoretical and experimental work has been devoted at this agency to a better understanding of non-stationary aerodynmics. 物理系统不存在奇异函数。
该机构为更好地了解非定常气体动力学作了大量的理论研究和试验工作。 第2节 翻译练习3
Animals are always losing carbon by respiration as against plants always gaining carbon.
The most effective method of reducing friction is to use rolling friction instead of sliding friction. 动物通过呼吸排除碳，而植物却吸收碳。
减少摩擦力的最有效的方法是采用滚动摩擦，而不是采用滑动摩擦。 第2节 翻译练习4
The shape of the electron spectrum in beta decay is not dominated by properties of the matrix element. Pressure in a liquid is at right angles to the walls of container. β衰变的电子谱的形状不取决于矩阵元的性质。 液体的压力与容器壁垂直。 第2节 翻译练习5
Hysteresis energy is a useful basis for the establishment of failure criteria in fatigue. Physical chemistry applies the methods of physics to the study of chemical systems. 在建立疲劳破坏准则时，迟滞能量是一个有用的依据。 物理化学是应用物理学的方法研究化学体系。 6.3 常用介词的译法 第3节 翻译练习1
Little information is given about the origin of life.
A basic change in thinking about force and mass is required.
Fluoride damage is generally restricted to areas about manufacturing plants. The vacuum was created about the exit. 关于生命起源方面的资料极少。
对于力和质量的看法需要做根本的改变。 氟化物的危害一般仅限于制造厂附近。 在出口附近产生真空。 第3节 翻译练习2
All of its circuit elements are bonded together after being manufactured. Line reams new bushings after installation.
After all logic events have been completed, the automatic control unit initiates the machine after the instruction.
将所有的电路元件在制成之后都连结在一起。 安装后对新轴套绞同心孔。
在所有的逻辑事件完成之后，自动控制器按照指令再次启动该机器。 Those machines are made after the model.
After all its changeable forms, energy can never be destroyed. 那些机器是按该模型制成的。
尽管能的形式是可以改变的，但绝不会消失。 第3节 翻译练习3
Working instruments are verified for calibration against reference instruments.
The current in a transmitting antenna when plotted against time is usually a sine wave. The process was against any basic laws of physics.
Force is necessary to drive an electric current against a resistance. 工业用的仪表要根据基准仪表来校验其刻度。
将发射天线中的电流相对于时间来描述出来，常是一正弦波。 该过程违背了物理学的基本原理。 驱动电流克服电阻需要有电动势。
One of the chief uses of zinc is to protect the surface of iron against rust. Lightening rods are used to protect electrical devices against lightening.
It is necessary to prevent induction motors against overload and undervoltage.
The advantages and disadvantages of each algorithm have to be weighted against each other in the light of the particular application.
锌的主要用途之一是防止铁表面生锈。 避雷针用来保护电器设备不受雷击。 必须保护感应电动机，防止过载及欠压。
每一种算法都必须根据具体应用相互对比才能权衡其优劣。 第3节 翻译练习4
The second phase of the restoration project will be to lay down a stabilization ring around the tower’s foundation.
The separating force on the mill was calculated to be around 10 million 1b.
The arch dam is economical in narrow canyons where the top chord length is around two to three times the height of the dam. 修复工程的第二阶段是在塔基周围建造一环形稳固基。 此轧机的轧制力量估计大约一千万磅左右。 截面越大，强度越大。 第3节 翻译练习5
Each observation could be weighted inversely as the distance or as the square root of the frequency. If the electric lines are parallel to the earth, the wave is referred to as horizontally polarized. 每次观测可以倒过来加权，作为距离或频率的平方根。 如果电力线与地面平行，其电波就称为水平极化电波。 第3节 翻译练习6
At the beginning of its operation, this turbine is only about 50 percent efficient. It is usual to provide a flowmeter at the column outlet.
A small hole is provided at the lock ring groove to facilitate removal of the lock ring. 在开始运行的时候，这台涡轮机的效率只有50%。 在柱子出口处常常要安装一个流量器。
为使锁定环拆卸方便，可在其沟槽内开一小孔。 The shunt motor operates nearly at constant speed.
Women of child-bearing age are at greatest risk, since their monthly bleeding is a major source of iron loss.
并励电动机差不多恒速运行。
育龄女性危险最大，因为月经是铁流失重要原因之一。 第3节 翻译练习7
And offshore drilling is made possible by using huge quantities of gaseous nitrogen and oxygen to provide a livable atmosphere deep under water.
Every metal possesses certain properties, or characteristics or qualities which we can find by experiment.
All materials are deformed to some extent by the application of an external force.
用大量的氮气和氧气形成在深水中能够生活的环境，才有可能进行海底石油钻探。 每一种金属都具有某些性能，或特性、性质，而这些我们可以通过实验检验出来。 所有材料多少都会由于外力而变形。（练习8用法） Nd
By the Law of Universal Gravitation, all bodies attract each other.
By this theory we can explain the phenomenon for which the old view of matter did not account. 按照万有引力定律，一切物体都相互吸引。
根据这一学说，我们就能解释旧的物质观没有说明的现象。 第3节 翻译练习8
The machine tool is directly driven by the main drive motor. The pituitary gland is constituted by two lobes.
The energy possessed by an object by virtue of its motion is called kinetic energy, or energy of motion. The production capacity has greatly increased by the development of the control of manufacturing processes by computers. 机床由主电机直接启动。
物体由于运动而获得的能量称为动能，或称为运动能量。 由于采用了计算机控制制造过程，因而生产能力大大提高。 垂腺体由两个叶组成。 第3节 翻译练习9
We may not have eliminated cigarette smoking completely by the end of this century. The faculty line must be repaired by the time of the summer harvest. The current in an inductor lags the voltage by 90° or, what is the same thing, the voltage leads the current by 90 °.
The experts calculate that this will straighten up the tower by several centimeters. 到本世纪末我们或许还不能完全消除吸烟现象。 夏收之前，故障线路必须修好。
根据专家们的计算，这将使斜塔取直几厘米。 电感器中的电流落后于电压90°，或者说，电压超前于电流90 ° 。 第3节 翻译练习10
By hPa we mean an international standardized pressure unit.
By conductivity we mean the ability to conduct an electric current. 所谓百帕，是国际上通用的表示气压的单位。 所谓导电率，是指传导电流的能力。 Nd
第3节 翻译练习11
The electric drive system is made detachable for ease of transportation and installation.
CFCs and other ozone-depleting chemicals were first mass-produced in the 1950s for use as refrigerants, industrial solvents, cleaning fluids and agents in making foam products. These data are the basis for important decisions.
They will build two power plants here, which can meet the demands for power supply. 为了便于运输和安装，电力驱动系统做成可拆式。
20世纪50年代，氟里昂和其他消耗臭氧的化工产品首次批量生产，它们主要用作制冷剂、工业溶剂、清洗液以及制造泡沫产品的制剂。 这些数据上做出重要决策的依据。
他们将在这里建两座电厂，这样便可以满足对电力的需求。 Nd
第3节 翻译练习12
The temperature was too high for the boiler to withstand.
A visual inspection must be done carefully for the materials, especially for those to be used in fabrication of pressure vessels.
For this reason, be very careful when you take antibiotics.
The first passengers came to ground, none the worse for their experience, 3,000 meters from their standing point.
温度提高，致使锅炉承受不了。
必须对材料仔细进行外观检查，对制造压力容器所用材料尤需如此。 由于这个原因，当你用抗生素时务必非常小心。
第一批乘客在离出发点3000米处着陆，并没有因这一 遭遇而发生不良反应。 Nd
第3节 翻译练习13
Make water do duty for alcohol as a solvent.
They succeeded in substituting a synthetic rubber for the natural rubber.
Electricity compensates for barometric pressure as well as system pressure variations. 用水代替酒精当溶剂用。
他们在用合成橡胶代替天然橡胶方面取得了成功。 用电补偿大气压力和系统压力的变化。 Nd
The disease raged through the city for months.
The mixture was cured at room temperature for 8-14 days. 这种疾病在这座城市猖獗了几个月。 混合物在室温下需熟化8-14天。 第3节 翻译练习14
For all their great stableness under ordinary circumstances, insulating materials may change radically in characteristics under extreme conditions of voltage stress or temperature or under the action of certain chemicals.
For all its invisible shield, the ozone layer can be measured in a number of ways. For all our advice, he insists on carrying out ignition experiment.
尽管在正常的情形下绝缘材料的性能很稳定，但在极端情况下，比如电压过高、高温或在某种化学物质作用下，绝缘材料的性能会遭到完全破坏。
尽管臭氧层是一种不可见的保护层，但还是有多种测量它的方法。 尽管我们劝阻他，他仍然坚持要进行点火实验。 Nd
第3节 翻译练习15
6
This reduces the resistance to current flowing from the wire through the rubber to copper strips below the tubes.
A user may jump from one document to another in a nonlinear, associative way.
From the information in this table, we can easily compute an estimate of the value of the mean of this grouped data.
Having no compass, he got his bearings from the sun. 轴承的载荷越大，其以转数为单位的寿命就越短。 动量作用线伸展得越远，角动量就越大。 截面越大，强度越大。 Nd
第3节 翻译练习16
Fabricate a shield from 12cm aluminum alloy to the dimensions shown on Figure 11. The electronic device is made from semiconductor.
Dead time is the time a worker losses from lack of materials or equipment breakdown. A similar error arises from neglect of multiple causes. 按图11所示，用12厘米厚的铝合金制造防护罩。 这只电子器件是用半导体做的。
无效时间是指工人因无原料或设备故障而失去的时间。 类似的错误可能由于忽视了多种原因而产生。 Nd
第3节 翻译练习17
The hardened washer shall be prevented from turning during locknut tightening. Washers shall be from burrs and sharp edges. The triggering circuit is immune from noise. The mixture are distinct from compounds.
Data is often distinguished from information and from programs. 当自锁螺母拧紧时应防止淬火垫圈转动。 这个触发电路不受杂音影响。 混合物不同于化合物。 垫圈不应带有毛刺和尖角。 数据通常有别于信息和程序。 Nd
第3节 翻译练习18
Highly poisonous insecticides should be kept from ordinary insecticides.
Electrolysis is the liberation of free elements from a liquid by passing an electric current through it. Place these parts in a plastic bag, and keep separate from other bearing assemblies. 剧毒农药和普通农药要严格分开置放。
电解就是让电流通过液体，从而使游离元素从液体中分离出来的过程。 将这些零件装进塑料袋中，和其他轴承部件分开置放。 Nd
第3节 翻译练习19
Canadian scientists looked for ozone thinning in the Arctic.
In Canada, governments are also starting programs to recycle and recover CFCs. The uses of industrial gases in our high-tech world are numerous and varied. 加拿大科学家在北极区寻找臭氧层变薄的迹象。
在加拿大，政府正在开展工作回收和循环使用氟里昂。
在我们这个技术高度发达的社会中工业气体的用途是多种多样的。 Nd
The hummingbird has the highest metabolic rate per unit of body weight in the avian world.
Although in recent years the liquid state has been the subject of intense study, the several books treat mainly the physics of this state.
In the 1970s, the focus of designing hardware was the creation of circuitry. 在鸟类世界中，单位体重的新陈代谢以蜂鸟为最高。
虽然近年来液态已成为努力研究的课题，但是这些书主要是谈论液态的物理特征。 在20世纪70年代，硬件设计的焦点是生成电路。 第3节 翻译练习20
The decision to repair is not easy, especially in borderline cases. All molecules are in constant motion.
In the study of lubrication and journal bearings, additional fundamental knowledge must be utilized. In order to prevent any damage or injury to human eyes in training, a laser energy attenuator may be mounted on the laser exit window.
做出返修的决定不是容易的，在可修可不修的情况下尤其如此。 在研究润滑和滑动轴承时，尚需用到另外的基础知识。
在训练时，为防止误伤人眼，可在激光输出窗口上装上激光能量衰减器。 一切分子都处在永恒的运动状态之中。 Nd
第3节 翻译练习21
The electric power which is consumed in an electric circuit is measured in watts or kilowatts.
Energy and work are both measured in joules. Power, being the amount of work done per second, is measured in watts (joules/sec).
电路中消耗的电力是以瓦或千瓦计量的。
能和功都用焦耳计量。功率是每秒钟所做的功，所以用瓦特（焦耳/秒）计量。 Nd
第3节 翻译练习22
Objects sink down into fluids until the upthrust equals the weight of the object.
If a permanent magnets is plunged into the coil the meter registers a momentary current. It is only recently that astronomers have begun specific research into black holes. 物体沉入流体，直到向上的推力与物体的重量相等。 如果把永久磁铁插入线圈，电表会记录到一次瞬间电流。 只是在最近，天文学家才开始对黑洞进行具体的研究。 Nd
Physics gives us power to adventure into the unknown. Heat transforms ice into water and water into steam.
The process converts iron and steel scraps into metal powder. 物理学给予我们探索未知世界的能力。 热使冰变成水，使水变成蒸汽。 此法可把钢铁切屑变成金属粉末。 第3节 翻译练习23
Considerable literature has grown up relating to experimental confirmation of elastohydrodynamic theory.
The successful launching of space rockets has added much to man’s knowledge of the upper strata of the atmosphere.
The processor is in over-all control of the system.
关于弹性流体动力润滑理论的实验证明，已涌现出大量文献。 宇宙火箭发射的成功大大增加了人类对大气上层的知识。 处理器对系统实施全面控制。 Nd
第3节 翻译练习24
These compounds are of the same family of organic materials.
All the types of memory we have discussed are of “random access”.
It might be thought that these two effects would be of the same order of magnitude. Today of the four only Earth is known to be tectonically active. 这些化合物属于同族有机物。
上述的各类储存期都属于“随机存取”类型。
人们可能会以为这两个效力的大小属于同一个数量级。
今天，在这四颗行星中，据人们所知只有地球的地壳构造仍在活动。 Nd
Of all forms of energy electricity is the most important. 在所有形式的能量中，电能是最重要的。 第3节 翻译练习25
A magnetic system is made of wrought iron arranged as in Fig. 8-16.
Flat belts are usually made of either oak-tanned leather or a fabric, such as cotton or rayon, which has been impregnated with rubber.
The motor consists of two parts, the stator and the rotor. 磁系统是由熟铁制成，如图8-16所示。
平型带通常用橡树皮鞣革或浸渍过橡胶的棉织品或人造纤维织品制成。 电动机由定子和转子两部分构成。 Nd
Each stage requires a different set of tools and sometimes requires different equipment and skills. 每一步都要求有一套不同的工具，有时还要求有不同的设备和技术。 第3节 翻译练习26
This chart may be plotted on semilog paper or on log-log paper.
Apply a small amount of the adhesive liquid on the face of the gasket.
Final composition of the Theater List is normally decided by the surgeon on the day prior to operation. On freezing, water does not contract, but instead it expands. 此曲线图可绘于半对数图纸或对数图纸上。 在密封垫表面上涂少许粘着剂。
接受手术人员的最后名单一般由外科大夫在手术前一天做出决定。 水结冰时，并不收缩，而是膨胀。 Nd
第3节 翻译练习27
Further research on this subject may suggest ways in which earthquakes can be predicted and prevented.
A good example of the local effects of pollution on weather is the increase in rainfall found in regions adjacent to a large paper mill.
The design of structures and drainage systems are not based on these adverse site conditions. 在这方面作进一步研究也许能提供预报和预防地震的方法。
污染对天气有局部影响，一个很好的实例就是在大型造纸厂附近地区降雨量有所增加。 工厂的建筑物和排水系统没有根据这些不利的厂址条件进行设计。
Relationships between voltages and currents in a circuit have been established on the experiments. On Bohr atomic theory and wave amplification theory, laser has been developed by scientists. 电路中电压与电流的关系已根据实验确定。
根据玻尔的原子理论以及波的放大理论，科学家们研制了激光。 第3节 翻译练习28
It relies heavily on digital processing.
On these observations, a hypothesis may be formulated. The motor is on the operation.
He developed pneumonia caused by blood clots in the lungs after traveling to Asia on an economy-class ticket.
这在很大程度上要依靠数字处理。 电动机在运行。
他在一次乘经济舱飞往亚洲之后，由于肺里产生血块而得了肺炎。 通过这些观察，可以作出一个假设。 Nd
第3节 翻译练习29
The prereduced or raw fine ore is injected into the smelting reduction furnace through the upper tuyeres.
Gases readily diffuse through porous solids.
The radiation could penetrate through layers of different materials.
经过预还原的矿粉或者原始的矿粉都是通过上部的风口送入熔融还原炉的。 气体很容易通过多孔固体渗出。 该辐射可以穿透多层不同的材料。
Through the combustion of the fuel, chemical energy is converted into heat energy.
The range and variety of work that can be done on a lathe are greatly increased through the use of various work-holding attachments.
Atomic energy has arrived in time to save civilization from dying through lack of power.
Silicon, chiefly through its better temperature characteristics, quickly replaced germanium in the power diode.
通过使用各种工件夹具，可大大扩大车床所进行的作业范围和种类。 由于硅有较好的温度特性，在功率二极管中，硅很快取代了锗。 通过燃料的燃烧，化学能转变为热能。
原子能已及时出现，从而拯救文明使其免于因能源短缺而灭亡。 第3节 翻译练习30
Magmas in transit to the surface will further supplement this heat.
The makeup water pipeline conveys the makeup water from the makeup water intake structure to the cooling tower basin.
A fresh cutter can be loaded to the spindle in a similar manner. 向地表移动的岩浆进一步补偿这种热量。
补给水管道把补给水从取水建筑物输送到冷却塔水池。 用同样的方法可将新刀具装在主轴上。
The function of the computer is not limited to providing support in solving mathematical problems. The system is restricted to examining the surface only.
Needed is a method of timing accurate to millionths of a second. Cultivation can be mechanized to the largest degree. 该系统仅限于检验金属表面。
耕作可在最大程度上实行机械化。
计算机的作用不能只限于帮助解决数学问题上。 需要有一种精确度达到几百万分之一秒的计时方法。 第3节 翻译练习31
Computers have as yet contributed little to pure mathematical theory. Air pressure is inversely proportional to altitude.
Thus, Fig. 5 is similar to Fig. 4b insofar as the same recombination and filters have been applied to both.
An electric motor is similar to a generator in construction. 迄今为止，计算机对纯数学理论的贡献不大。 气压与高度成反比。
电动机和发电机在结构上类似。 第3节 翻译练习32
Water enters the cylinder and fills the space under the piston.
When a vehicle passes over a road, its weight is transmitted through the wheel on to the pavement under it.
But how can bouncing sound waves help oceanographers to see the sea floor and the mud, soil, and rocks under it?
水进入泵筒，并注满活塞下面的空间。
当一辆车驶过马路时，其重量通过车轮传至车下的路面上。
而反射波怎样帮助海洋学家去考察海底以及下面的泥、土和岩石呢？
Under certain conditions, heat energy may be changed into mechanical energy, and mechanical energy (may be changed) into heat energy.
There is no material but will deform more or less under the action of forces. Water vapor in the air breaks down under the intense heat. 在力的作用下，一切材料无不变形。
在一定条件下，热能可以转换成机械能，机械能也可以转换成热能。 空气中的水蒸气在高温下发生分解。 第3节 翻译练习33
Under some trade terms, the buyer might undertake to clear the goods for export in the seller’s country.
7
The books are categorized under the Dewey Decimal System. The agreement for the trade and cooperation is still under a draft. Lianyungang Nuclear Power Station is still under construction.
根据某些贸易条款规定，买方须负责在卖方所在国的出口清关。 这些图书是按照杜威十进制编目的。 贸易合作的协定仍在草拟中。 连云港核电站仍在建设中。 第3节 翻译练习34
It has no connection with the automatic positioning facilities. Oxygen is a gas that can unite with many substances. The resistance usually varies with temperature. 它与自动定位装置没有关系。
氧是一种能与许多物质化合的气体。 电阻常常随温度变化。
With the invention of the transistor, electronics entered a new phase.
With the advance of science and technology, some scientific problems become less complicated than they were thought.
随着晶体管的发明，电子技术进入了一个新的阶段。
随着科技进步，有些科学问题没有原先认为的那么复杂了。 第3节 翻译练习35
The machining center is provided with an automatic tool changer.
Bricks are also produced in many different colors and with various finishes. Most of the machining we do in a machine shop is done with cutting tools. Unix marketers have looked with some envy at these applications. 加工中心备有自动换刀装置。
砖也可以烧成不同的颜色，具有不同的光洁度。
我们在机械加工车间所做的大部分机加工是用刀具来进行的。 “UNIX”的销售者以很大的热情关注着这些应用程序。 第3节 翻译练习36
With the advent of modern methods of communication the whole world has been transformed into a single mechanism.
The machines may get heated with overload.
Computers perform particular operations with the information they are given. 由于近代通信方法的出现，整个世界已转变为一个统一的机体。 机器可因过载而发热。
计算机根据所收到的信息进行特定的运算。
Assemble bearing inner and outer races with serial numbers indexed. An interrupt is allowed to occur in accordance with specified priorities. 根据特定的优先权允许发生中断。 根据序号组装轴承内外座圈。 第3节 翻译练习37
With its many advantages, wood is not without its drawbacks as a fuel. With its complex structure, it is liable to install.
With no discovery, many laws of nature actually exist in nature. With slight repair, the old type of engine can be used. 尽管木材有许多优点，但作为燃料仍有缺陷。 虽然结构复杂，但容易安装。
许多自然规律虽然尚未被发现，但它们确实存在于自然界之中。 只要稍加修理，这台老式发动机就可使用。 第3节 翻译练习38
Petrol is a mixture of the lower-boiling hydrocarbons, with boiling temperatures ranging from 100°C to 400°C.
Never operate the engine with the water temperature in the radiator exceeding 100°C.
The field-effect transistor consists of a single crystal of doped semiconductor material in the shape of a bar with leads connected to both ends. 在散热器中的水温超过100°C的情况下决不要开发动机。
场效应晶体管是一个棒状的掺杂半导体材料的单晶，两端连有引出线。 汽油是低沸点的碳氢化合物混合体，其沸点范围在100°C to 400°C之间。 With the cause of the fault removed at once, the generator kept working.
One kind of switch is inside a metal box called a switch box, with a handle on the outside. The pressure of a gas varies inversely as its volume, with temperature constant. With the switch open, there is no current flowing in the load.
有一种开关是放在一个称作开关箱的金属箱内，而柄留在外面。 由于即使排除了故障，发电机继续工作。 温度不变时，气体压强和体积成反比。 打开开关，没有电流通过负载。 第3节 翻译练习39
Magnetic induction can take place without contact between the magnet and the iron. Without dust, there would be no clouds and no rain.
Thin plates are joined by melting their edges together without the addition of filling metal. 磁铁和铁块相互不接触便可发生磁感应。 若没有灰尘，就不会形成云和雨。
薄钢板是靠熔化其边缘而焊接在一起的，不需要填料金属。 A body cannot be moved without having a force act upon it. He finished the stress experiment without difficulty. 他轻松地完成了这个应力实验。
若没有力作用于物体上，物体就不能移动。 第6章 总复习题
The conductivity of polyacetylene drops rapidly in contact with air. There is a brighter future for intelligent devices in the home.
The scientists found that the blood vessels in the leg cannot swell.
Once upon a time, bold claims were made about computers, the future and the “paperless office”. 聚乙炔一接触空气，其导电性就迅速下降。 家庭智能装置仍有着更加光明的前景。（省译） 科学家们发现腿内的血管不会肿胀。
曾几何时，有人就有关计算机、未来和“无纸化办公”做过大胆的预测。 The doctor advised against the use of the new treatment.
If a good base cannot be found at a reasonable depth, then a so-called deep foundation must be provided.
Magnetic lines of force cannot be seen, but we know they exist by what they do. 磁力线是看不见的，但是我们按照它们的作用即知它们的存在。 医生建议不要使用新的治疗方法。
若在合理的深度内找不到坚实的地基层，那就要采用所谓的深基础。 We may process directly with Kirchoff’s voltage law for the circuit. The proper values of a and b are determined from two conditions. Optional communications are free from electromagnetic interference. This type of discrepancy could have resulted from differences in kinetics. a和b的值由两个条件决定。
对于电路，我们可直接从克希荷夫电压定律讲起。 光电通信不受电磁的干扰。
这种差异可能是由动力的不同而造成的。
The visual image of the letters making up the word is converted into its spoken equivalent. Primitive man made weapons, tools, and utensils of copper, brass, and bronze.
The longer wavelengths of radio signals pass through the atmosphere relatively undisturbed. 将组成词的各字母的视觉形象转换成该词对应的发音。 相对来说，波长较长的射电讯号通过大气时没有受到干扰。 原始人类用铜、黄铜和青铜制作成各种武器、工具和器皿。
Most hardness-testing systems employ a standard load which is applied to a ball or pyramid in contact with the material to be tested.
All metals are corrodible under the proper circumstances.
The design of the rocket nozzle also has much to do with the behavior of the exhaust and the resulting velocity of the vehicle itself.
多数的硬度实验系统使用一标准载荷加在与实验金属相接触的小球或棱锥上。 所有金属在一定情况下都是可腐蚀的。
火箭喷管的设计与排气的性能及飞行器本身的有效速度有很大关系。
Peripheral milling operations are usually performed on milling machines with the spindle positioned horizontally; however, they can also be performed with end mills on vertical-spindle machines. Copper and aluminum are the best conductors of electric current only after silver. From various experiments we cannot but think the theory still holds good. 周铣作业通常在带有水平定位主轴的铣床上进行，但也可以在带有端面铣刀的主轴铣床上进行。 铜和铝是仅次于银的最好的导电体。
根据各种实验，我们不得不承认这个理论依然是行之有效的。 Hydrogen is generated from zinc and sulfuric acid.
The sort of fish cannot live in the temperate zone, let alone in the frigid zone. The locomotive developed some new problems on its line-test. Gases can be chemisorbed or physically absorbed on solids. 氢由锌和硫酸所产生。
这种鱼不适合在温带生活，更不必说在寒带了。 这台机车在试运行时出现了一些新问题。 气体能化学吸附或物理吸附在固体上。
Under ideal conditions the fatigue failure will consist of a spotting of the load-carrying surfaces. Oxidation implies the combination of other elements with oxygen to form compounds. 在理想条件下，疲劳失效将是承载表面的点蚀。 氧化意味着其他元素与氧形成化合物。 7.1 连词的一般译法 第1节 翻译练习1
Carbon steel contains only iron and carbon, while alloy steel contains some other alloying metals. Because this current continually reverses in direction, it is called an alternating current. Liquid and vapor phases cannot coexist in equilibrium.
碳钢只含有铁和碳，而合金钢含有一些别的合金金属。 由于这种电流不断地改变方向，故称为交流电。 液相和气相不能在平衡中并存。 第1节 翻译练习2
Some companies replace certain parts regularly, determining the effective life of a part and then replacing it just before it would wear out.
The cost of making these tests is very low when it is divided by the total number of parts manufactured.
一些公司定期更换某些零部件，先推定零部件的有效寿命，以便在零部件即将磨损之前予以更换。
如果以生产零件的总数来划分，这些实验的成本会非常低。 Why use metal when you can use plastic?
A brief description of how transistors are manufactured is given here. That is why surfactants are so widely used in industry. 既然能用塑料为什么你却使用金属呢？ 这里对晶体管的是生产方法作一简略叙述。 这就是在工业上广泛使用表面活性剂的原因。 第1节 翻译练习3
Sometimes it is necessary to drill to a depth of 1,000 meters or more, before water is found in sufficient quantity.
It is stated that the positioning system has an accuracy of repeatability within 0.0002 inch. When short waves are sent out and meet an obstacle they are reflected. 有时必须钻到1000米或更深的深度，才能找到足够量的水。 据称，该定位系统的重复精度在0.0002英寸。 短波发送出去，遇到障碍就反射回来。 7.2 常用并列连词的译法 第2节 翻译练习1
Computers cope with negative numbers and fractions in binary arithmetic. Oxygen is chemically active and takes part in many reactions. 计算机采用二进制算法来处理负数与小数。 氧的化学性能活泼，能参与许多反应。（省译）
Modern electronic computers and other devices will be made smaller by the development of LSI.
Some electrical engineers design and maintain power plants, transmission lines and home and factory electrical installations.
大规模的集成电路的发展将使现代化电子计算机以及其他装置越来越小。
有些电气工程师设计和保养发电厂、输电线、以及各种家用和工业用电器设备。 第2节 翻译练习2
The induced electromotive force lags and the current leads. Like charges repel and unlike charges attract. 感应电动势滞后，而电流导前。 同性电荷相斥，异性电荷相吸。（省译）
Transformers are commonly used in radio receivers and electrical communication circuits, and they are generally much smaller than those for power transmission.
Analyzing the dynamics of the way a person signs his or her name, and not just how the signature looks, is one basis of a biometric verifier.
变压器通常用于无线电收音机和电信电路中，可是这些变压器一般比用于输电的变压器小得多。 分析一个人签名时书法的笔力，而不只是分析签名的字形如何，这是生物统计学核实器的一个基本点。
第2节 翻译练习3
It is important to know that different types of control circuits may be used in one control system, and a completed control loop may consist of a combination of electric, pneumatic, or hydraulic elements. 重要的是要知道，在一个控制系统中可使用不同类型的控制电路，而且一个完整的控制回路可由电力、气动或液压配合组成。
The synchronous motor is even more expensive and requires a source of d.c. excitation, as well as special synchronizing control to apply the d.c. power at the correct instant. Telephone communication is now widespread and efficient. The machine is old and heavy.
同步电动机则更贵，而且需要直接励磁电源和专门的同步控制器以便在适当的瞬间接入直流电源。
现在的电话通讯既广泛又有效。 这台机器又旧又笨重。 第2节 翻译练习4
We have to replace some of its parts and make this machine more efficient.
To make the balloon descend, the “pilot” opened a valve and allowed some of the gas escape. 我们必须调换某些零件，以使这台机器效率更高。
为使气球降落，“飞行员”打开阀门，以使部分气体逸出。
Change one or more steps and we will improve the quality of the finished products.
Use a transformer and we can transform power at low voltage into power at high voltage and vice versa.
若改变一个或几个步骤，我们就有可能提高成品的质量。
用了变压器，我们就可以把低电压变为高电压，也可把高电压变为低电压。 第2节 翻译练习5
Uncap openings in indicators and connect lines.
Install aluminum washers nest to pump, steel washers next, and install nuts. Lead lacks tensile strength and it cannot be drawn out in the form of fine wire. 取下仪表开口处的盖子，再接上管路。 铅的张力差，因此不能制成细丝状。
8
紧贴泵处安上铝垫片，然后加钢垫片，再安上螺栓。
For LP turbine there is no residual axial thrust caused from blading because of the turbine’s double-flow arrangement of blading and thus no balancing piston is needed.
至于低压汽轮机，并没有残存的轴力，因为汽轮机的叶栅作双流配置，因而也无需采用平衡轮。 第2节 翻译练习6
The plan is very complicated technically, but the general idea is quite simple.
Now the electrons which have been driven onto the negative plate are trying to get back to the positive plate, but cannot do so because of the e.m.f which is applied to the plates. 这一计划在技术上十分复杂，但总的想法却相当简单。
现在已被赶到负极上的电子力图返回正极，可是由于极板上施加有电动势的缘故而办不到。 There are already a number of modern vehicles which are not yet in common use, but which may become a usual means of transport in the future.
现在已有一些现代化的运载工具，它们目前尚未被普遍使用，但将来可能成为一种日常的交通工具。
第2节 翻译练习7
But that he prevented me, I might have kept the machine parts in the damp place.
But that the checking up of the experimental data had taken so much time, we should have completed our work long ago.
若不是他阻止，我可能就会把那些机器零件保存在潮湿的地方。 假若检验这些实验数据不花那么多时间，我们早就完成了这项工作。 But for air, the earth would undergo extreme changes in temperature.
But for the laws of motion as a basis, thousands of discoveries and inventions would have been out of the question.
要是没有空气，地球温度就会发生剧变。
如果没有运动定律作为基础，就不可能有成千上万的发现和发明。 第2节 翻译练习8
The positive and negative ions become separated or dissociated.
No electric charges have been observed of smaller magnitude than the charge of protons or electrons. Foods quick-frozen in liquid nitrogen or carbon dioxide have transformed the way we eat. 正负离子彼此分解或电离。
还没有观察到比质子或电子的电量更小的电荷。
用液态氮或二氧化碳速冻的食物已改变了我们的饮食习惯。
We will start with a cubic inch of hydrogen at atmosphere pressure (or the air pressure at the earth’s surface).
Scientists have shown that certain chemicals are slowly eroding the ozone layer. The main culprits are chlorofluorocarbons or CFCs.
Fire is a chemical action, or an action taking place between different chemical substances. 我们从大气压力（即地球表面的空气压力）下的一立方英寸氢气开始。
科学家们已经证明，某些化工产品会慢慢破坏臭氧层。主要诱因就是氯氟甲烷，即氟里昂。 火是一种化学反应，也就是发生在不同化学物质间的一种作用。 第2节 翻译练习9
Right or wrong, his theory is the most influential.
All methods, simple or complicated, are employed in the tension-test. You have to open the switch right away or else the fuse will be burned off. 无论对错，他的理论无疑是最有影响力的。
在拉伸试验中，所有方法不论简单还是复杂，都用过了。 你必须把开关立即断开，否则保险丝就会烧断。 A body must move, or no work is done.
These old transformers have been used for ten or twenty years.
The newly-installed generating set will be put in operation a month or so. 物体必须移动，否则就没有做功。
这些旧变压器已经使用大约一二十年了。 新机组再有一个月左右就投入运行。 第2节 翻译练习10
The central computer’s job is to run through the maps in its database as well as details on road works, weather, etc.
Boiling point elevations, as well as the variation of the heat capacities and latent heats with temperature, are negligible.
中心计算机的任务是查阅储存在数据库中的地图以及修路工程、天气等详细情况。 沸点升高以及热容和潜热随温度的变化而忽略不计。
He discovered that he could send the sound of music as well as the dot-and-dash sounds of Morse Code through the coil.
The physics students study chemistry as well as physics.
他发现不仅能使线圈传送莫尔斯电码的点划音，而且也能是线圈传送音乐。（倒译法） 物理系学生不仅学物理，而且要学化学。（倒译）
Experimental data can be used to illustrate the application techniques as well as to demonstrate the validity of the approach.
In order to get various vitamins a person should eat a diet including vegetables as well as meat. 实验数据既能用来说明应用技术，也能用来验证方法的有效性。（顺译） 为了摄取多种维生素，一个人既应该吃些素食，也该吃荤食。（顺译） 第2节 翻译练习11
When light strikes an opaque object, the light is either absorbed or reflected. The oxygen contained in the rocket is either in the liquid or in the solid form. When astronomers look at the sky, they expect to see either a star or a galaxy. 当光照在不透明的物体上时，光或是被吸引或是被反射。 火箭内储存的氧或是液态的，或是固态的。
每次天文学家观测天空，他们期望看到的不外乎是一个恒星或一个星系。 第2节 翻译练习12
There are materials which are neither good conductors nor good insulators. It is neither possible nor practical to make many parts to an exact size. Neither glass nor porcelain is a conductor.
有些材料既非良好的导体也非良好的绝缘体。
要使许多零件加工尺寸丝毫不差，既不可能，也不切实际。 玻璃和陶瓷都不是导体。 第2节 翻译练习13
Not only does air exert pressure, but it also has buoyancy.
This method not only simplifies analysis but also facilitates measurements. 空气不仅产生压力，而且有浮力。
这种方法不仅简化了分析，而且也便于测量。 7.3 常用主从连接词的译法 第3节 翻译练习1
The loop oscillator frequency can be the same as, or a multiple of , the reference frequency.
Because a d.c. motor is the same physical machine as a d.c. generator, its equivalent circuit is exactly the same as that of a generator except for the direction of current flow. 环路振荡器可以和参考频率相同，也可以是参考频率的倍数。
由于直流电机与直流发电机的物理结构是一样的，其等效电路除了电流方向外也与直流发电机相同。
R2, as is shown in Fig. 3, has been split in halves to enable the feedback to be applied. Under certain conditions a body can be charged, as has been said before. 如图3所示，R2被分为两半，使得反馈能够加上去。 在一定的条件下，物体能够带电，这在前面已经讲到。 第3节 翻译练习2
As current is increased, the flux builds up according to Curve 2. As you are doing the experiment, write down the observations. 当电流增大，磁通沿着曲线2增大。
在你做实验的同时，把观察到的情况记录下来。
As the 21st century approaches, complicated digital technologies and the promise of exploding bandwidth are combining to create a third kind of convergence. As particle has no extent, its position is a point. As water is a compound, it can be decomposed.
As the current was trebled abruptly, the second valve burnt out.
随着21世纪的来临，复杂的数字技术与带宽不断扩大的前景相结合将会创造出第三种意义的“连通”。
由于质点没有广度，它的位置是一个点。 因为水是化合物，所以可以分解。
由于电流突然增加了两倍，第二个电子管烧坏了。 第3节 翻译练习3
Gravity, the force of the earth’s attraction, governs the atmosphere just as it governs solid objects. Some waves are reflected as a mirror reflects light.
The large force is to the small force as the large area is to the small area. 引力，即地球的吸引力，正像它影响着固体那样影响着大气。 大的力与小的力之比就像大面积与小面积之比。 有些波被反射，就像镜子反射光一样。
Electron tubes are not so light in weight as semiconductor devices. The tools are machined to tolerances as close as 0.0001 inch.
Modern computers can store the facts as fast as they are gathered and pour them out whenever they are needed.
电子管的重量不如半导体器件那么轻。
现代计算机能尽快地将收集到的资料储存起来，并在需要时输送出去。 工具加工的误差接近0.0001英寸。 第3节 翻译练习4
Complicated as modern machine is, it is essentially a combination of simple machines.
The various losses in a machine, great as they are, do not in any way contradict the Law of Conservative of Energy.
Very large as the nuclear energy supply in the interior of the star is, it is nevertheless finite. 现代化机器虽然复杂，但实质上不过是许多简单机械的组合。 虽然恒星内部的核能储量很大，但仍是有限的。
机器中的各种损耗尽管很大，但这与能量守恒定律丝毫也不矛盾。 第3节 翻译练习5
Each of the two wires carrying currents has a magnetic field, as if it were a magnet. Water also presses on the inside of the container as though it is trying to escape. 通电的两根导线每一根都有一个磁场，好像是一块磁铁。 水对容器的内壁也产生压力，似乎水力图要流出来一样。 第3节 翻译练习6
So long as we have means of producing heat can we keep a steam engine working. It is capable of keeping its shape as long as the planet keeps spinning. 只要设法产生热，就能使蒸汽机做功。
只要恒星连续不断地旋转，它就能保持自己的形状。
As far as processing power is concerned, the difference between a PC and a mainframe is closing fast. As far as the quality of transformers is concerned, the ones they produced are better. 就处理能力而言，PC机和大型机之间的差异正在迅速缩小。 就变压器的质量而言，他们生产的变压器更好。 第3节 翻译练习7
As soon as printing quality levels can be maintained and the effective life of the machine increased, a preventive maintenance program is effective.
As soon as the electrons are transformed and ions formed, they are charged. The electrons create a magnetic field as soon as they begin to move.
一旦印刷质量得以保证并且机器有效使用期得以延长，经常性维修保养计划才是行之有效的。 一旦电子转移，形成离子，它们就带电了。 电子一开始运动，就产生磁场。 第3节 翻译练习8
Before you join one electric wire with another, make sure the current has been switched off. The leaves separate before the metallic board is touched.
Further study is needed before the origin of the covalent bond can be considered a settle question. 在你把一根电线和另一根电线连接起来之前，务必先切断电源。 在接触金属板以前簧片分开。
需进一步深入研究，才能解决共价键的起源问题。
The direction of the current was decided before electrons were discovered. She switched on the engine before we could stop her. 电流方向确定了，电子才被发现。
我们还没来得及阻止她，她就开动了发动机。 第3节 翻译练习9
Even if one of the engines fails the plane will be able to continue its flight safely.
It has undergone a chemical change since, even if cooled, it will not return to its original condition. The lathe can turn holes even if it is not a driller.
即使发动机中有一台失灵，飞机仍能安全地继续飞行。 车床尽管不是钻床，也能钻孔。
从那时起它已发生化学变化，即使加以冷却，它也不会恢复原样。 第3节 翻译练习10
If a.c. power is available, all drives requiring constant speed should use squirrel-cage induction or synchronous motors because of their ruggedness and lower cost.
If the parting contacts are made of low-melting-point material such as brass or copper, the arc will go out at the first current zero as the voltage is insufficient to reestablish as cathode spot after current reversal.
因为鼠笼式感应电动机或同步电动机经久耐用且成本低，若有交流电源可用，所有需要恒速驱动的装置应使用这两种电机。
如果分段的触点采用低熔点金属（如黄铜、铜）等制作，则电弧会在第一个电流过零点熄灭，因为在电流极性变化后，没有足够的电压再次产生阴极辉光放电。
People might have avoided many accidents if ultrasonic methods had been known. If a d.c. system were to be used, the transmission loss would be very great. If there were no air, the earth would undergo extreme changes in temperature.
The question is if there are other chief sources of organic materials in addition to coal and petroleum. 要是过去知道超声波法，人们当时是可以避免许多事故的。 如果没有空气，地球温度就会发生剧变。 若采用直流电力网，输电损失就会很大。
问题是除了煤和石油之外是否还有别的有机物主要来源。 第3节 翻译练习11
The current flows through a conductor in case there is a difference of potential between the ends of the conductor.
Ordinary movements would be impossible in case friction were unavailable. 如果导体两端有不同电位时，电流就可以通过导体流动。 假如没有摩擦力，常见的活动都不可能进行。 第3节 翻译练习12
Once formed, the depletion region acts against further diffusion.
Once the melting point is reached, the temperature will not increase any further until the melting is completed.
Once an object is in motion, it will continue to move. 耗尽区一旦形成，便会阻碍进一步扩散。
一旦达到熔点，温度就不再升高，直到完全熔化。 物体一旦处于运动状态，就会继续运动下去。 第3节 翻译练习13
The pressure of a gas is inversely proportional to its volume provided its temperature is kept constant. The blast-furnace is expected to remain the world’s chief source of iron units steelmaking, provided adequate supplies of suitable coking coal remain available at competitive cost. 如果温度保持不变，则气体压力和其体积成反比。
只要有足够的焦煤且成本低，高炉仍将是世界上主要的炼铁设备。
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All substances will permit the passage of some electric current, in the event that the potential difference is high enough.
The magnetic effect does not represent a continuous expenditure of energy, supposing that the current is steady.
倘若电位差足够高时，所有的物质都将可能通过若干电流。 假如电流稳定的话，磁效应不再继续消耗能量。 第3节 翻译练习14
Since that time, especially since the introduction of the Bessemer process, the age of iron has turned into an age of steel.
Electricity has found wide application since it was discovered.
自从那时起，特别是自从采用贝西默炼钢法以来，炼铁时代转变为炼钢时代。。 自从发现电以后，电就获得了广泛的应用。
Since planetesimals aggregated at different distances from the sun’s heat and light, the composition of the planets varies.
Since the secondary winding is normally operated into a high-impedance circuit, the secondary current is quite small.
由于微星聚集的地点离太阳的热和光远近不同，行星的组成也不同。 因为次级绕组通常被输入高阻抗的电路，所以次级电流很小。 第3节 翻译练习15
Large accumulations of plant remains indicate that the deposits were formed in close proximity to land in a swamp, estuary, or delta.
One condition for this is that the polymer consists of alternate single and double bonds, termed conjugated double bonds.
若是植物遗骸大量堆积，这表明沉积物是在紧靠陆地的沼泽、港湾或三角洲中形成的。（宾从） 一种情况是，这种聚合物由单双键交替构成，即所谓的共轭双键。（表从）
We are all familiar with the fact that nothing in nature will either start or stop moving by itself. The pore space of soil that is thoroughly soaked with water does not have any air.
This could result in the development of tiny, powerful computers that run for extended periods of time on little power.
我们都熟知这样一个事实：自然界没有一个物质会自行开始运动或自行停止运动。（同位从） 完全被水浸没的土壤，其孔隙没有丝毫空气。（定从）
这种技术可以用于开发体积微小、功能强大的计算机。而这类计算机依靠极少的电能就可以长时间地工作。（定从） 第3节 翻译练习16
Many substances such as glass and wood conduct so poorly that they may be called nonconductors or insulators.
At an estimated 80 beats per second, the bee hummer’s wings move so rapidly that the naked eye cannot detect them.
诸如玻璃、木材之类的物质传导性极差，所以可称为非导体或绝缘体。（结果状从） 蜂鸟的翅膀估计每秒扇动80次，速度之快使肉眼看不到它的翅膀。（结果状从） Cables are usually laid underground so that their life may be extended.
Now that we have examined several areas of natural science, perhaps it would be well to attempt to define science.
Lead is toxic in that it hampers brain development. 电缆通常安装在地下，为的是延长其寿命。（目的状从）
既然我们已经仔细研究了自然科学的几个领域，现在不妨给科学下个定义。（原因状从） 铅有毒，因为铅会影响大脑发育。（原因状从） 第3节 翻译练习17
Unless the steam is superheated, higher pressure will be necessary. A copper wire is not affected unless there is electrical pressure. Usually substances can’t expand, unless they are heated. 如果蒸汽不是过热蒸汽，就需要较高的压力。 铜线不受磁铁的影响，除非它载有电流。 物质如果不受热，一般是不会膨胀的。 第3节 翻译练习18
Until the SCR was developed, the thyratron was the only controlled rectifier available. Rubber was known only as a natural product until its synthesis was achieved in 1916. Not until the jet engine had come into use could planes travel at supersonic speeds. 在研制出可控硅之前，闸流管是唯一可用的可控整流元件。
在1916年人工合成橡胶之前，人们只知道橡胶是一种天然产品。 直到喷气发动机投入使用，飞机才能做超音速飞行。
When the water temperature is increased, it vaporizes more quickly until it reaches boiling point. 水温升高时，水蒸发得越来越快，直到达到沸点为止。 第3节 翻译练习19
Precisely what happens to the atomic structure of metals at such low temperatures is still not wholly understood.
Since sound travels differently through different materials, analyzing the sounds can reveal what the floor is made of.
在如此低的温度下金属的原子结构到底发生什么变化，还不完全清楚。（主从）
因为声音在不同的物质中传播情况不同，分析这些声音能够知道海底是由什么构成的。（宾从） A programmer must make out, in every detail, the problem to be solved in what is called machine language.
These illustrations show what happens to the mixture after it enters the cylinder of the engine.
The method of physics is to analyze first the simpler cases, to extract what we can from them, and to go forward to more and more complicated cases. What the image tube does is not hard to describe.
程序编制人员要用所谓的机器语言把要解决的题目详尽地编排出来。（宾从） 这些插图显示混合物进入汽缸后会发生什么情况。（宾从） 显象管的作用不难说清。（主从）
物理学的方法是首先分析一些较简单的事例，从中吸取我们所能吸取的知识，然后进一步分析越来越复杂的事例。（宾从） 第3节 翻译练习20
We don’t know when the best times are for seeing Mercury.
We don’t know when they can give the transformers we ordered.
This was the period when he began the research which resulted in the creation of his famous Theory of Relativity.
我们不知道观察水星的最好时机是什么时候。（主从） 我们不知道他们什么时候开始交付我们订购的变压器。（宾从）
就在这期间，他开始进行一项研究，通过这项研究创立了著名的相对论。（定从）
In those years when electricity had not been discovered, people knew nothing of conductors and insulators.
在电还没有被发现的年代里，人们不知道有导体和绝缘体。（定从） 第3节 翻译练习21
When a substance is dissolved in water, the freezing point of the water is lowered. The SCR will only pass current when its gate is pulsed.
Newton’s first two laws hold only when they are observed in unaccelerated reference frames. 当一种物质溶解于水时，水的冰点就会降低。
只有当可控硅的门电极受脉冲作用时才能让电流通过。
牛顿的第一、第二定律，只有在非加速的参照系中作观察时，才能成立。 An electric current exists when there are charges in motion. 如果有电荷运动，就存在着电流。 第3节 翻译练习22
Where the power station will be built is under discussion.
Universal connectivity will bring together all the information and services you need and make them available to you regardless of where you are, what you are doing, or the kind of device you are using. 电站建在什么地方正在讨论中。（主从）
通用连接技术将能把你所需要的信息和服务收拢起来。而且无论你在哪里，无论你在做什么，无论你使用何种设备，它都能将这些信息和服务送到你手上。（宾从） Then arose the question where we were to buy the generators needed.
Water power station must be built where there are water falls. Where the watt is too small a unit, we may use the kilowatt.
这时就产生了这样一个问题，我们到哪儿买所需要的发电机？（同位从） 水电站必须建在水有落差的地方。（状从） 在用瓦作单位太小的情况下，我们可用千瓦。（状从） 第3节 翻译练习23
Resistant and tolerant varieties can help mitigate tuber damage where nematodes are present.
Most urban areas now have a TDD relay center, where operators serve as intermediaries between TDD users and standard-phone users.
Surrounding every magnet there is a region where magnetic forces act. 在每一块磁铁的周围都有一个磁力作用的区域。（定从） 抗病虫品种可以有助于减缓线虫对球根的损害。（定从）
现在大部分城市市区都有“耳聋电信装置”中继中心，在那里接线员是“耳聋电信装置”用户和普通电话用户的中间人。（定从）
The reducing top gas, containing 70 percent carbon monoxide plus hydrogen, flows from an outlet pipe located near the top of the DR furnace into the top-gas scrubber, where it is cooled and scrubbed to remove dust particles. 第3节 翻译练习24
The question is whether these relays and breakers come up to the mark. We wonder whether simpler and more inclusive conservation laws exist. There is no difference whether or not the temperature is kept constant. A waterfall, whether it is man-made or natural, also possesses energy. 我们不知道是否有形式更简单、运用范围更广泛的守恒定律。（宾从） 温度是否保持不变，这没有什么关系。（同位从） 问题是这些继电器和断路器是否合乎要求。（表从） 瀑布，不管它是人造的还是天然的，也具有能量。（状从） 第3节 翻译练习25
Which of these generators is the most efficient has to be tested. The problem is which generator you repair first.
As to which of these apparatuses is the best, I can’t give you any definite answer. 这些发电机中哪一个最有效还有待试验。（主从）
至于这些装置中哪台最好，我不能作任何肯定的回答。（宾从） 问题是你先修哪一台发电机。（表从） 第3节 翻译练习26
Technology tries to find applications for new ideas which science discovers.
In order to keep the engine speed within the limits which it was designed for, a device which is known as a governor is incorporated in the engine.
The basic principle which a tape recorder functions on is that of magnetism. 技术力图为科学所发现的新思想找到应用。（定从）
为了使发动机的转速保持在所设计的范围之内，在发动机里装有被称为调速器的装置。（定从） 磁带录音机的基本工作原理就是磁性原理。（定从）
Molecules in turn are made up of atoms, which are smaller particles still.
An experimental station has been established off the Ivory Coast of Africa, which utilizes the different temperature levels of sea water.
Light has a higher frequency than radio vaves or microwaves, which gives it a greater information carrying capacity.
分子本身又是由原子构成，后者是更小的粒子。（定从） 在非洲象牙海岸沿海已建立起一座试验性发电站，该发电站利用海水的温度级差来发电。（定从） 光的频率高于无线电波和微波，这就使它具有更大的信息运载能力。（定从）
At present, microwave technology, which includes microwave heating and microwave survey, is being widely applied to industrial and agricultural production.
Many people could find that videoconferencing yields productivity gains which make it worth the investment of time and money.
目前，微波技术，包括微波加热和微波测量，正广泛地应用于工农业生产。（定从） 许多人会发现，视频会议系统可以提高生产效率，因此它值得我们投入时间和金钱。（定从） 第3节 翻译练习27
Motion is absolute while stagnation is relative.
New types of computers are smaller in size, while they are simpler in operation. Each face is an equilateral triangle, while three faces meet at each vertex. 新型计算机体积较小，而且操作也比较简单。
每一个面是一个正三角形，而且在每一个顶点有三个面相交。 运动是绝对的，而静止是相对的。 第3节 翻译练习28
While a crystal solid melts, there is no change in temperature. While there are heat losses in a steam turbine, I cannot prove it.
While a spark of life remains, it is a doctor’s duty to save the patient. 当晶态固体熔化时，温度没有变化。
虽然涡轮机内有热损耗，但我无法加以证明。 只要病人还有一息生机，医生就有责任挽救。 第3节 翻译练习29
It is still not clear in my mind why a generator can produce power. This is why some conjugated polymers exhibit electro-luminescence. We all know why the ground loses heat to the air. 我仍然弄不明白为什么发电机能发电。（主从）
这就是为什么一些共轭聚合物具有电致发光的特点。（表从） 我们都知道为何地表把热量输送给空气。（宾从）
The reason why elements emit radioactive rays is that they are constantly decaying. The reason why the turbine doesn’t work is the lack of lubricant. 元素射出放射线的原因是因为它们不停地在衰变。（定从） 那台汽轮机运转不灵的原因是缺少润滑油。（定从） 第7章 总复习题
The conductivity of polyacetylene drops rapidly in contact with air. There is a brighter future for intelligent devices in the home.
The scientists found that the blood vessels in the leg cannot swell.
Once upon a time, bold claims were made about computers, the future and the “paperless office”. 聚乙炔一接触空气，其导电性就迅速下降。 家庭智能装置仍有着更加光明的前景。（省译） 科学家们发现腿内的血管不会肿胀。
曾几何时，有人就有关计算机、未来和“无纸化办公”做过大胆的预测。 The doctor advised against the use of the new treatment.
If a good base cannot be found at a reasonable depth, then a so-called deep foundation must be provided.
Magnetic lines of force cannot be seen, but we know they exist by what they do. 磁力线是看不见的，但是我们按照它们的作用即知它们的存在。 医生建议不要使用新的治疗方法。
若在合理的深度内找不到坚实的地基层，那就要采用所谓的深基础。 We may process directly with Kirchoff’s voltage law for the circuit. The proper values of a and b are determined from two conditions. Optional communications are free from electromagnetic interference. This type of discrepancy could have resulted from differences in kinetics. a和b的值由两个条件决定。
对于电路，我们可直接从克希荷夫电压定律讲起。 光电通信不受电磁的干扰。
这种差异可能是由动力的不同而造成的。
The visual image of the letters making up the word is converted into its spoken equivalent. Primitive man made weapons, tools, and utensils of copper, brass, and bronze.
The longer wavelengths of radio signals pass through the atmosphere relatively undisturbed.
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