6、月球绕地球一周（make one revolution about the earth）需花27.3天。
7、这种情况分析起来特别简单。
8、科学知识被应用到实际生活事务（practical affairs of life）中去需要花费许多时间和劳力（labor）。
9、在各种物质（substance）导热（conduct heat）能力方面差异是很大的（there are wide differences）。
10、万有引力（gravity）是所有物体相互吸引的趋势。
11、这一单元确定要执行（perform）这些运算中的哪一个。 12、在有些实验中，你将会被告知要测量什么和使用什么仪器。 III、改正下列句中的错误，并将句子译成汉语：
1. A force is any influence that can cause a body accelerated（加速）. 2. The boundary condition is found to not affect the correlation（关系）.
3. It is always a good policy checking the results by substituting the values of the unknowns into the original equations to see that the values satisfy the equations.
4. All we need do is rubbing one thing against another.
5. Light is to consider as some kind of wave motion of electromagnetic origin.
6. Let it to be required to develop（展开）f (x) into a Fourier’s series（傅氏级数）. 7. For solids, density（密度）is a bit more difficult to be determined.
8. The tendency for a satellite to keep moving round the earth is an example of inertia（惯性）.
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练习 12
I、英译汉
Part A：说明划线部分的语法功能，然后将句子译成汉语：
1. Any measurement made is the ratio of the measured magnitude to an accepted unit of measurement.
2. Hydrogen is the lightest element known. 3. Steady electric current can be produced by the electric cell（电池）, invented by the Italian physicist Allessandro Volta (1745 – 1827). 4. Distance is equal to speed multiplied by time. 5. The waves become weaker with the increased temperature.
6. Lacking knowledge of just what these radiations were, the experimenters named them simply alpha, beta, and gamma radiation, from the first three letters of the Greek alphabet. 7. Recently delivered to the Air Force Air Defense Command, this unit is the first in a series of high-power multibeam systems for detection of aircraft at high altitudes（高空）and extreme ranges（超远）.
8. An angle in radians, being defined as the ratio of a length to a length, is a pure number. 9. The maximum efficiency, neglecting the loss in Re, is only 40%. 10. VBE varies between 0.3 and 0.7 V, depending on the base current（基极电流）.
11. A valence electron（价电子）can move away from its atom, leaving it a hole（空穴）. 12. In this case electrons will possess more energy, so increasing the brightness of the spot（光点）.
13. At the resonant（谐振的）frequency the current has its largest possible value, assuming the voltage to be constant regardless of frequency. 14. The design problem may be solved using a microprocessor. 15. As we advance from hydrogen to the more complex elements, we find the electrons contained in a series of energy levels（能级）. 16. Any impedances（阻抗）associated with the source of emf（电源）must be left connected in the network. 17. A power reactor（电力反应堆）having no need of air, we can build it underground. 18. The purpose and general guidelines of each experiment are given, the details being left to the instructor. 19. Now let us determine the path of a projectile（抛物体）, the resistance of the air being neglected.
20. In Group I, we have hydrogen and the alkali metals（碱金属）, all of low density and chemically very active. 21. In the domain of reals（实数域）the functions ex and log x are inverses（反量）, the one of the other. 22. There are many reasons for this, among them the fact that simulation（仿真技术）allows the assessment of the potential before a newly designed system is operable. Part B：划出下列句中的“with结构”，说明其语法功能，并将句子译成汉语： 1. With this in view, we have attempted to write this book. 2. A slide projector is to be used with its lens 29 ft from a screen.
3. Standard screws are all right-handed, with left-hand ones employed only for special purposes.
4. A ladder 12 ft long rests against a vertical frictionless wall with its lower end 4 ft from the wall.
5. We write z = x + jy, with x and y real.
6. The current gain（电流增益）βn shall be measured with Ep grounded.
7. Each planet revolves around the sun in an elliptical（椭圆的）orbit, with the sun at one focus of the ellipse（椭圆）.
8. The Internet Protocol (IP) was not designed with security in mind.
9. The nucleus of hydrogen consists of a single proton with a single electron revolving about it. 10. All present states（目前状态）are stable with no inputs present.
11. Equations with radicals in them are normally solved by squaring both sides of the equation. 12. The equation to the circle with its center at the origin and of radius a is x2 + y2 = a2. 13. That device with buttons on it is a keyboard.
14. Equation (2 – 1) is called the standard equation of the ellipse with its major axis along the x-axis and its center at the origin. II、汉译英
Part A：将下列句子译成英语，要求对划线部分用分词（短语）来表示： 1、这是由五部分构成的一种设备。
2、电阻（resistance）等于电压（voltage）除（divide）以电流（current）。 3、流过电路（circuit）时，电流会遇到一些阻力（opposition）。
4、若用公式表示的话，这个定律可写成如下形式（as follows）。 5、这电池（battery）如果使用得当，可以维持很长的时间。 6、一个力可以分解（resolve）成两个分量（component），其中一个是垂直的（vertical），另一个是水平的（horizontal）。
Part B：将下列句子译成英语，要求对划线部分用“with结构”表示： 1、让我们以原点（origin）为圆心（center）、作一个半径（radius）为R的圆（circle）。 2、一个很小的（tiny）原子核（nucleus）处于原子的中央，其电子离它一段距离。 3、如果不存在摩擦（friction），能量就不会损失掉。
4、在设计这个设备时，考虑到了安全问题。
5、v正比于（proportional to）F的方程可以这样来解。 6、键盘（keyboard）就是上面带有按键（button）的设备。 III、改正下列句中的错误，并将句子译成汉语： 1. Giving V and I, we can find out R.
2. No existed textbooks describe this phenomenon. 3. This is an illness resulted fron eating too much.
4. Students used this book have completed a course in Mechanics.
5. The higher the temperature, the greater the number of electrons emitting. 6. Speed is equal to distance dividing time.
练习
13
I、说明划线部分的语法功能，并将句子译成汉语：
1. Enzymes（酶）increase the speed of chemical reactions without being changed themselves. 2. We refer to such elements as being passive（无源的）. 3. When a cell（细胞）has reached its limit of growth, it reproduces（繁殖）by dividing in two. 4. An angle is defined as being generated by rotating a half-line（射线）about its endpoint from an initial position to a terminal position.
5. On reaching state b, the system remains in that state.
6. The following table may be helpful in converting measurements to different units. 7. In erecting a receiving aerial（天线）, attention must be paid to the factors affecting reception.
8. Seeing examples solved in detail gives readers a certain amount of feeling for the problem solving process and subject material.
9. Substituting these values in the second equation shows that that solution checks. 10. It is worth doing this experiment.
11. It is no use removing the charged body（带电体）away. 12. Magnetism has long stopped being a problem. 13. Let us consider designing a voting machine. 14. Mechanization is using machines instead of hand labor. 15. We call this analyzing the waveform.
16. This procedure is called rationalizing the denominator. 17. Heat is simply a phenomenon of molecules moving. 18. Aluninum can never be found free in nature, because of its always being combined with other elements. 19. We know of the earth?s acting as a big magnet. 20. Automation is not a question of machines replacing man.
21. The solution of these independent equations often results in certain of the currents being negative. 22. A current flows through the resistors（电阻器）as a result of there being a potential difference（电位差）across it. 23. All oscillators（振荡器）tend to drift（漂移）in frequency unless steps are taken to stop them doing so.
24. Operation beyond this hyperbola（双曲线）will result in diode（二极管）power dissipation（功耗）in excess of its maximum rating of 1 W.
25. The existence of minimum portions (quanta) of energy prevents our being able to describe the motion of atomic particles in the conventional way. 26. The controlling of the temperature is a typical example of a feedback control system. II、将下列句子译成英语，要求对划线部分用动名词（短语）表示：
1、产生电的方法有多种。
2、瓦特（watt）是用来测量电路（circuit）中消耗（expend）的功率的一种单位。 3、这个电容器（capacitor）可以通过被连接到电池上来充电（charge）。
4、在对上述方程整理（rearrange）后，我们得到了以下的方程组（set of equations）。 5、在使用上面的那个方程时，要注意符号（sign）。 6、迅速地压缩（compress）气体就能提高它的温度。
7、反馈（feedback）涉及到（involve）取出一小部分输出并馈回（feed back）到前一级（preceding satge）去。
8、条件越拥挤（crowded），爆发（break out）流行病（epidemics）的机会就越大。 III、改正下列句中的错误，并将句子译成汉语：
1. To place an electric potential difference（电位差）across some material generally results in a flow of electric charge（电荷）.
2. This experiment is worth being done.
3. It is essential to avoid to make wrong connections of the polarities（极性）of this capacitor（电容器）.
4. The problem is we not having sufficient instruments for the experiment. 5. This is the commonly used way of AC changing into DC.
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练习 14
I、将下列句子译成汉语，注意句中的各类状语从句：
1. A body at rest will never move till force compels it.
2. The values of most things must be converted from decimal to binary before computations can begin.
3. One linear factor（线性因子）appears each time a root（根）is found. 4. These double-angle formulas（倍角公式）can be used any time we have expressed one angle as twice another.
5. Where one curve crosses the x-axis, its y-value is zero.
6. Now that we know the acceleration（加速度）of the block（木块）, we can determine the time required for it to travel 200 ft.
7. Nonlinear（非线性）networks are much more difficult to analyze than linear networks, for
no general method can be used for their solution. 8. Nature has no objection（反对）to a violation of energy conservation（守恒）, provided the violation does not last too long.
9. As far as electrical effects are concerned, fundamental particles（基本粒子）come in three different kinds, neutral, positive, and negative.
10. The magnet is usually made in the shape of horseshoe（马蹄）so that it will be as strong as possible.
11. The solution to this equation must be such that if we substitute it into the left side, we obtain the right side.
12. This circuit is only accurate at frequencies low enough that its capacitive reactance（容抗）can be neglected.
13. A current alters the properties of space in its vicinity such that a piece of iron there experiences a force.
14. No matter what the value of B, the ratio between A and B remains constant.
15. In figuring（计算）the concepetal acceleration（向心加速度）of the moon, we tacitly assumed the earth to be stationary while the moon circled around it. 16. While this logic（逻辑电路）seems correct, it will not work.
17. Some liquids are of high fluidity（流动性）, while others are very viscous. 18. While energy is the capacity to do work, power is the quantity of work in unit time. II、将下列句子译成英语：
1、该球直到遇到障碍物（obstacle）时才会停下来。
2、当无线电波沿着地球表面传播（travel）时，会丢失掉一部分能量。 3、虽然原子核（nucleus）很小，它是由更小的单元构成的。（要求使用“as”） 4、这两个图（diagram）是相同的（identical），只不过原子上的方向是相反的。 5、就电压（voltage）而言，这个电路等效于（be equivalent to）图1-3的那个电路。
6、我们在日常生活中是如此习惯于使用斜面（inclined plane），以至于可能很难把它看成为（think of … as）一种“机械（machine）”。 7、不论物体的温度有多低或多高，它们都发射（emit）出热射线（heat ray）。 8、在发电机（generator）工作期间，电压总是存在的。
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练习 15
I、将下列句子译成汉语，注意句中的同位语从句：
1. The discovery that current can be produced by magnetism is extremely important in the field of electricity.
2. The idea that electricity cannot be created or destroyed may seem to imply that electrons and protons cannot be created or destroyed.
3. That fact that everything around us is matter is known to all.
4. In this case, the condition that the function（函数）must exist is not satisfied. 5. There can be no doubt that the magnetic field is produced by some sort of circulating electric current.
6. This follows from the necessity that the two forces be equal.
7. R=r is the condition that power delivered by a given source is a maximum.