fundamentals of power electronics 答案 problem3.6
电子信息专业英语习题答案
第一单元元件与定律A．课文译文电阻器、电容器和电感器在电子电路中，电阻器、电容器和电感器是非常重要的元件。
电阻器和电阻电阻器是二端口元件。
电阻是阻止电流流动，更确切地说，是阻止电荷流动的能力。
在国际单位制中，电阻用欧姆来度量。
希腊字母Ω是欧姆的标准符号。
较大的电阻一般用千欧和兆欧来表示。
模拟这种特性常用的电路元件是电阻器。
图1.1表示电阻器的电路符号，R表示电阻器的电阻值。
图1.1 电阻器的电路符号为了进行电路分析，我们必须在电阻器中指明电流和电压的参考方向。
如果我们选择关联参考方向，那么电压和电流之间的关系是：v=iR(1.1) 这里v是电压，其单位是伏特，i是电流，其单位是安培，R是电阻，其单位是欧姆。
如果选择非关联参考方向，我们必须写成：v=－iR(1.2) 用在公式（1.1）和（1.2）中的代数式就是著名的欧姆定律。
欧姆定律表示了电压作为电流的函数。
然而，要表示电流是电压的函数也是非常方便的。
欧姆定律是电阻两端的电压和电流间的代数关系。
电容器和电容电能可以存储在电场中，存储电能的装置叫电容器。
电容器存储电能的能力叫做电容。
图1.2表示电容器的电路符号。
电容的电路参数用字母C表示，用法拉来度量。
因为法拉是相当大的电容量，实际上电容值通常位于皮法和微法之间。
图1.2 电容器的电路符号当电压随时间变化时，电荷的位移也随时间变化，引起了众所周知的位移电流。
在终端，位移电流和传导电流没有区别。
当电流参考方向和电压参考方向是关联参考方向时，电流正比于电容两端电压随时间的变化率的数学表达式为：dt dvC i = (1.3)这里 i 的单位是安培，C 的单位是法拉，v 的单位是伏特， t 的单位是秒。
电感器和电感众所周知，电感是电子电路中的模块之一。
所有的线圈都有电感。
电感是抵抗流过线圈电流的任何变化的性质。
电感用字母L 表示，其单位是亨利。
图1.3表示一个电感器。
图1.3 电感器的电路符号当电流和电压的参考方向关联时，有dt diL v = (1.4)这里v 的单位是伏特，L 的单位是亨利，i 的单位是安培，t 的单位是秒。
95年硕士电子学模拟考考题
百度文库专用95年碩士電子學模擬考考題一單選題（每題2分，答錯者倒扣0.5分）1. 對一pn二極體而言，下列何者敘述為真？(a) 順向電流隨溫度增加而增加(b) 逆向電流隨溫度增加而減小(c) 順向偏壓之介面電容(junction capacitance)小於逆向偏壓之介面電容(d) 以上皆真。
【中央電機所】2. A類輸出級在功率電晶體散逸功率最大時的功率轉換效率為(a) 0% (b) 10% (c) 25% (d) 50% 【台大電機所】3. B類輸出級在功率電晶體散逸功率最大時的功率轉換效率為(a) 0% (b) 25% (c) 50% (d) 78% 【台大電機所】4. Which one of the followings is NOT true for a CMOS inverter?(a) ratioless logic(b) n o static power dissipation(c) dynamic power dissipation inversely proportional to the switchingfrequency(d) c urrent flows only at transition. 【台大電子所】5. Which of the followings is not the basic characteristics we would assume forideal operational amplifiers?(a) slew rate (b) infinite input impedance(c) zero common mode gain (d) infinite bandwidth(e) zero output impedance. 【清大動力機械所(乙)】6. What is the main advantage of ECL as a logic gate?(a) Power (b) Area (c) Speed(d) N oise (e) Cost. 【台大電子所】7. What is the true statement for a voltage doubler circuit consists of twodiodes and two capacitors?(a) The two capacitor have AC voltage. (b) T he two diodes have DC voltage.(c) One capacitor parallels to the output terminal. (d) I nput source can be DC voltage.(e) Two capacitors are directly connected. 【清大動力機械所(乙)】8. In describing the GS D v i - characteristics of MOSFET, what is the most irrelevant terminology to be considered in the followings? (a) channel length modulation (b) saturation region (c) triode region (d) process transconductance parameter (e) W/L ratio. 【清大動力機械所(乙)】9. Which of the following statement is true?(a) a common-gate amplifier has an infinite input resistance(b) a common-base amplifier ’s current gainiA is larger than 1(c) an emitter follower has an infinite output resistance(d) a common-emitter amplifier can have a voltage gain >1 and a current gain>1 simultaneously. 【中央電機所(乙丙丁)】10. For the operational amplifier circuit, please choose a proper illustration for the offset voltage.(a) An input offset voltage means that the output voltage is zero when th input signal voltages are zero.(b) O ne source of an offset voltage is a mismatch in the differential pair transistor parameters and/or mismatches in active load transistor parameters.(c) Variations in temperature will not produce variations in offset voltage. 【高雄應用科大電子所】二、連鎖題（每題2分，答錯者倒扣0.5分）甲. A feedback circuit is shown in Fig.1, the OP amp has open-loop gainV/V 104=μ, Ω=k 100id R and Ω=k 1o r . Use the feedback analysis. (11) Identify the feedback topology to be used.(a) Shunt-Series (b) Series-Series (c) Shunt-Shunt (d) Series-Shunt(12) Find the voltage gain (s o V V /).(a) -96V/V (b) -192V/V (c) -48V/V (d) -108V/V (e) -288V/V (13) Find the input resistance in R .(a) 15Ω (b) 29.9Ω (c) 60Ω (d) 1.23Ωk (e) 108Ωk (14) Find the output resistance out R(a) 29.5Ω (b) 60Ω (c) 120Ω (d) 1.23Ωk (e) 160Ωk【中央電機所(乙丙丁)】乙. 如Fig. 2所示為一CMOS 反相器，I v s1μ=T時。
电子科技英语试题及答案
电子科技英语试题及答案一、选择题（每题2分，共20分）1. Which of the following is not a feature of electronic components?A. High precisionB. High reliabilityC. Low power consumptionD. Large size答案：D2. What is the basic unit of digital information?A. BitB. ByteC. KilobitD. Megabyte答案：A3. In electronics, what does the term "analog" refer to?A. Continuous signalsB. Discrete signalsC. Digital signalsD. Binary signals答案：A4. Which of the following is not a type of semiconductormaterial?A. SiliconB. GermaniumC. PlasticD. Gallium arsenide答案：C5. What is the function of a transistor in an electronic circuit?A. To amplify signalsB. To store dataC. To convert light into electricityD. To filter signals答案：A6. What is the primary function of a capacitor in an electronic circuit?A. To block DC and allow ACB. To block AC and allow DCC. To store electrical energyD. To convert voltage into current答案：C7. What does the abbreviation "LED" stand for in electronics?A. Light Emitting DiodeB. Large Emitting DiodeC. Limited Emitting DiodeD. Low Emitting Diode答案：A8. What is the purpose of a resistor in an electronic circuit?A. To control voltageB. To control currentC. To store energyD. To amplify signals答案：B9. Which of the following is a type of passive component in electronics?A. TransistorB. DiodeC. RelayD. All of the above答案：D10. What is the term used to describe the flow of electric charge?A. VoltageB. CurrentC. ResistanceD. Capacitance答案：B二、填空题（每题2分，共20分）1. The smallest unit of electric charge is called an ________.答案：electron2. A ________ is a type of electronic component that can store energy in an electric field.答案：capacitor3. The process of converting sound into electrical signals is known as ________.答案：modulation4. In digital electronics, a ________ is a single digit number, either 0 or 1.答案：bit5. A ________ is a semiconductor device that can amplify or switch electronic signals and electrical power.答案：transistor6. The unit of electrical resistance is the ________.答案：ohm7. An ________ is a semiconductor device that allows current to flow primarily in one direction.答案：diode8. The ________ is a passive component that opposes the flow of alternating current.答案：inductor9. A ________ is a type of display device that uses liquid crystals to produce images.答案：LCD10. The ________ is a type of electronic component that can store data.答案：memory三、简答题（每题10分，共20分）1. Explain the difference between an analog and a digital signal.答案：Analog signals are continuous and can represent a wide range of values, while digital signals are discrete and can only represent specific values, typically as a series of ones and zeros.2. Describe the role of a microprocessor in a computer system. 答案：A microprocessor is the central processing unit of a computer system, responsible for executing instructions, performing calculations, and controlling other system components to perform various tasks.四、翻译题（每题15分，共30分）1. Translate the following sentence into English: “在电子设备中，晶体管通常用作放大器或开关。
电力电子技术基础—驱动
晶闸管的触发电路 ——单结晶体管组成的简易触发电路
• C的充电时间常数 1 ReC ，决定脉冲电压uG的产
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• Re的取值范围
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晶闸管的触发电路
——同步信号为锯齿波的触发电路
6
电力电子器件的驱动和保护
——驱动保护电路概述
➢ 驱动电路——主电路与控制电路之间的接口
➢ 使电力电子器件工作在较理想的开关状态，缩 短开关时间，减小开关损耗，对装置的运行效 率、可靠性和安全性都有重要的意义
➢ 对器件或整个装置的一些保护措施也往往设在 驱动电路中，或通过驱动电路实现
➢ 驱动电路的基本任务： ➢ 将信息电子电路传来的信号按控制目标的要求， 转换为加在电力电子器件控制端和公共端之间， 可以使其开通或关断的信号 ➢ 对半控型器件只需提供开通控制信号 ➢ 对全控型器件则既要提供开通控制信号，又要 提供关断控制信号
South China University of Technology
Fundamentals of Power Electronics Technology
电力电子技术基础
第二部分 电力电子器件
第四章 电力电子器件的驱动和保护
South China University of Technology
电力电子器件的驱动和保护 ——驱动保护电路概述
➢ 驱动电路还要提供控制电路与主电路之间的 电气隔离环节，一般采用光隔离或磁隔离
➢ 光隔离一般采用光耦合器 ➢ 磁隔离的元件通常是脉冲变压器
50本电力经典书籍 -回复
50本电力经典书籍-回复「50本电力经典书籍」是一个非常具有挑战性的主题，因为电力工程这一领域没有像文学或者历史等领域一样广为人知的经典著作。
然而，我们可以通过对电力工程相关主题的深入研究，找到一些经典书籍，这些书籍对于电力工程师、学生和研究人员来说都是不可或缺的资源。
电力工程是涉及电力生成、传输、配电和电力系统运营的学科。
在这个广阔的领域中，有许多书籍提供了有关发电、配电、传输线路、电力系统规划、保护和控制等方面的知识。
从基础原理到应用实践，以下是50本被广泛认可的电力工程经典书籍：1.《电力系统分析》（Electric Power Systems Analysis）- John J. Grainger, William D. Stevenson这本书作为电力工程领域的经典教材，涵盖了电力系统分析的许多基本原理。
2.《电力系统稳定》（Power System Stability）- Edward Wilson Kimbark 这本参考书为电力系统稳定性提供了深度的理论和实践知识。
3.《电力系统保护》（Protective Relaying）- J. Lewis Blackburn, Thomas Domin该书详细介绍了电力系统保护的原理和技术。
4.《电力系统的有功和无功控制》（Active and Reactive Power Control of Electric Power Systems）- Takashi Kaneda该书介绍了有关有功和无功控制的先进方法和技术。
5.《电力电子和电力驱动系统: Fundamentals and Hard-switching Converters》- Bimal K. Bose这本书提供了电力电子和电力驱动系统的基础知识，深入讨论了硬开关变换器。
6.《电离害电、地欠电压与电网故障》(Electromagnetic Transients in Power Systems) - R.D. Begamudre该书详细介绍了电磁暂态现象对电力系统的影响以及如何控制它们。
华北电力大学大学本科专业培养方案——电气工程及其自动化
电气工程及其自动化专业人才培养方案Electrical Engineering and Its Automation一、学制与学位Length of Schooling and Degree学制：四年学位：工学学士学位Duration：4 years Degree：Bachelor of Engineering二、培养目标Educational Objectives培养适应社会主义现代化建设需要，德智体全面发展，具有较强的综合素质和一定的创新精神，能够从事电气工程及其自动化领域相关的工程设计、生产制造、系统运行、系统分析、技术开发、教育科研、经济管理等方面工作的特色鲜明的复合型高级工程技术人才。
本专业设电力系统及其自动化（电力）、继电保护及自动远动技术（电自）、高电压技术（高压）、城市供用电（城电）、电力电子技术（电力电子）、电力市场等6个专业方向。
This program is designed to provide students a comprehensive education in all areas of moralism, intelligence and physical to meet the demand of socialized modernized construction. Graduates from the program are expected to be integrated senior engineers with strongly comprehensive capability and innovative spirit, capable for all electrical engineering and its automation related areas such as engineering design, electrical production, power system operation and analysis, technology development, education and research, financial management, etc. This major consists of 6 specialized directions: power system and its automation (power system, in short), protection relay and remote technology (protection), high voltage technology (high voltage), city power supply technology (city power supply), power electronic technology, and electricity markets.三、专业培养基本要求：Requirements of Educational扎实地掌握数学、物理等自然科学基础知识，具有良好的人文社会科学和一定的经济、管理科学基础知识，并熟练掌握一门外语；系统地掌握本专业领域必需的专业基础理论知识，并具有较强的计算机应用能力；具有本专业领域内1个专业方向的基本专业知识与实际操作技能，了解本专业领域的理论前沿和发展动态；获得较好的工程实践训练，具有综合解决工程实际问题的能力；具有较强的知识获取与运用能力，具备创新意识和从事科学研究、科技开发的能力；具有较强的工作适应性、人际交往能力和团队协作精神，具有一定的组织管理才能。
电气工程专业英语-2 Fundamentals of Solid-state Power Device
Fig. 2.7 shows the schematic symbol for a triac. A triac consists of a special thyristor package with forward and reverse thyristors operated from a single gate lead. They are commonly used in light-dimmer circuits and as on -off relays where slight leakage currents in the offstate will not cause mis The availability of triacs with increased ampere capabilities has led to their use in phase control of AC motors.
Fig.2.5 shows the junction arrangement, schematic symbol, and volt-ampere characteristic for a typical power transistor.
图2.5给出了三极管的半导体材料分层结构、电气符号、和典 型功率三极管的伏安特性 。
图2.7为双向可控硅的电气符号，它由共用一个门极端的 正向和反向可控硅的特殊封装构成，它通常用于调光电路或作 为延时开关，在这种场合中，它关断时的漏电流很小，不会导 致其它控制设备的误操作。大电流容量双向可控硅的实用化， 使得它们在交流电机的相位控制方面得到应用。
The differences among the three physical types of power semiconductors have largely to do with how they are mounted and connected to their heat sinks.
电力系统常用英语词汇
电力系统 power system 发电机 generator 励磁 excitation励磁器 excitor 电压 voltage 电流 current升压变压器 step-up transformer 母线 bus 变压器 transformer空载损耗:no—load loss 铁损：iron loss 铜损:copper loss空载电流：no—load current 无功损耗：reactive loss 有功损耗：active loss 输电系统 power transmission system高压侧 high side 输电线 transmission line高压： high voltage 低压：low voltage 中压：middle voltage功角稳定 angle stability 稳定 stability 电压稳定 voltage stability暂态稳定 transient stability 电厂 power plant 能量输送 power transfer交流 AC 直流 DC 电网 power system落点 drop point 开关站 switch station 调节 regulation高抗 high voltage shunt reactor 并列的：apposable 裕度 margin故障 fault 三相故障 three phase fault 分接头：tap切机 generator triping 高顶值 high limited value 静态 static (state)动态 dynamic (state) 机端电压控制 AVR 电抗 reactance电阻 resistance 功角 power angle 有功（功率) active power电容器:Capacitor 电抗器:Reactor 断路器：Breaker电动机：motor 功率因数:power-factor 定子：stator阻抗电压: 阻抗：impedance 功角：power-angle 电压等级：voltage grade有功负载： active load/PLoad 无功负载：reactive load 档位:tap position 电阻：resistor 电抗：reactance 电导：conductance电纳：susceptance 上限：upper limit 下限：lower limit正序阻抗：positive sequence impedance 负序阻抗:negative sequence impedance 零序阻抗：zero sequence impedance无功（功率） reactive power 功率因数 power factor 无功电流 reactive current斜率 slope 额定 rating 变比 ratio参考值 reference value 电压互感器 PT 分接头 tap仿真分析 simulation analysis 下降率 droop rate 传递函数 transfer function框图 block diagram 受端 receive—side 同步 synchronization保护断路器 circuit breaker 摇摆 swing 阻尼 damping无刷直流电机：Brusless DC motor 刀闸(隔离开关）：Isolator 机端 generator terminal变电站 transformer substation永磁同步电机：Permanent-magnet Synchronism Motor异步电机：Asynchronous Motor三绕组变压器：three-column transformer ThrClnTrans双绕组变压器：double—column transformer DblClmnTrans固定串联电容补偿fixed series capacitor compensation双回同杆并架 double—circuit lines on the same tower单机无穷大系统 one machine - infinity bus system励磁电流：magnetizing current 补偿度 degree of compensation电磁场Electromagnetic fields 失去同步 loss of synchronization装机容量 installed capacity 无功补偿 reactive power compensation故障切除时间 fault clearing time 极限切除时间 critical clearing time强行励磁 reinforced excitation 并联电容器:shunt capacitor下降特性 droop characteristics 线路补偿器 LDC（line drop compensation）电机学 Electrical Machinery 自动控制理论 Automatic Control Theory电磁场 Electromagnetic Field微机原理 Principle of Microcomputer电工学 Electrotechnics电路原理Principle of circuits电机学Electrical Machinery电力系统稳态分析 Steady—State Analysis of Power System电力系统暂态分析 Transient—State Analysis of Power System电力系统继电保护原理 Principle of Electrical System's Relay Protection 电力系统元件保护原理 Protection Principle of Power System ’s Element电力系统内部过电压 Past Voltage within Power system模拟电子技术基础 Basis of Analogue Electronic Technique数字电子技术 Digital Electrical Technique电路原理实验Lab。
大学知识课件(作为考研考试参考)：电力电子技术基础5—可控整流
一周期中，在t1~t2期间，VD1导通，ud=ua 在t2~t3期间， VD2导通，ud=ub 在t3~ t4期间，VD3导通，ud=uc
PW = 2ms MCR3918-10A
V0-V
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V 2 = 15
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V 0V
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第三部分 电力电子变换电路
电力电子技术基础 第三部分 电力电子变换电路 ——单相全桥全控整流电路的特点
克服了单相半波可控整流电路 的缺点：电流脉动小，消除了 变压器的直流分量，提高了变 压器的利用率。
在小容量设备里边得到应用。
电力电子技术基础 第三部分 电力电子变换电路 ——电阻性负载
VT3
VT1
工作原理及波形分析 VT1和VT4组成一对 桥臂，在u2正半周承 受电压u2，得到触发 脉冲即导通，当u2过 零时关断 VT2和VT3组成另一 对桥臂，在u2正半周 承受电压-u2，得到触 发脉冲即导通，当u2 过零时关断
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2018年国家电网公司电力英语水平考试辅导书阅读理解答案总结
阅读理解1.Wind energy has numerous benefits(1)The reason for[ out](2)Why is wind[ pollution](3)Which of the following statements[ locations](4)Which of the following is one[ maintenance](5)The cost of[ wind]2.Strange thing happens to time(1)The best title[ world](2)The difference[ hour](3)F orm this[ zones](4)The international[ begins](5)If you cross[ hours]3.As a clean and renewable energy(1)What’s the feature[ source](2)Before installing[ be done](3)According to the[ phone masts](4)Which of following is[ pollution](5)Which of the following statements[ turbines] 4.Doctors have known for(1)Doctors have[ noise](2)This passage[ be….more than one second](3)According to this[ worse](4)M illions of[ aspirin](5)The purpose[….from loud noises]5.Cell phones are not just distracting(1)M any people[ closed](2)What will happen[ influenced](3)What do children[ and night](4)Why do children[ cell phones](5)The author[ sometimes]6.In our present life everything is(1)M any things[ signals](2)Which of following is[ quickly](3)Doctors can use [ diseases](4)Which of the following statements[ computers](5)What is the[’s life]7.When it comes to the advantages(1)F or a company’s business[ process](2)What is the purpose[ source](3)What is a step[ design](4)Who is needed[developer expertise](5)What does specialized[]8.Not every purchase goes as planned(1)When making[ person](2)What should[](3)What should be[](4)What does the[ complaints](5)What method[ network]9.When most people think of scuba(1)Usually most[ waters](2)How can divers[ first](3)What is the[ than in other waters](4)Why can some[ warm](5)What can be[ tubes of ice]10.P eople appear to be born to computer(1)What does[ children](2)F orm the passage[ and walk](3)In this passage[](4)According to[’t think](5)Which of the[ easily]11.A new technology is going to ripe(1)As is indicated[ development](2)The new technology[ the word](3)What does the[](4)F orm the passage[ technology](5)Which of the[:a new technology]12.Online banks revolutionized brick-and-mortar(1)What should[ phones](2)One of advantages of[ banks](3)If you lose you[ phone](4)Which of the[ account](5)What’s the[ banking]13.All the useful energy at the surface of(1)The sun is[ power](2)Radiant energy[](3)The sun’s energy[](4)The largest part[’s atmosphere](5)Of the sun’s total[ portion]14.The market is a concept(1)Which of the following[ market](2)All of the[ school](3)Y ou are buying[ restaurant](4)The word [](5)In what way[ produce]15.Business development(BD) is a(1)What is the final[ opportunities](2)Why is a strong[ succeed](3)If a football[ concerned](4)What is important[ the departments](5)What is the passage[ development]16.“Body clocks”are biological(1)According to[a.”body clock”］(2)Irregular signs[ illnesses](3)We tend to[ then](4)The author[ night](5)According to the[ time]17.Plastics are materials which are(1)The word[](2)It can be[ antiues](3)Which of the following is necessary[](4)Plastics that harden[](5)Which of the following is the best[ material]18.When we analyze the salt salinity(1)This passage[ salinity](2)It can be[](3)Which of the following is[ ice](4)Which of the following statements[ the oceanic salinity](5)The purpose of[ salinity]19.The science of meteorology is(1)Which of the following is the best[ science of mereorology](2)The predictions of[ maps](3)Which of the following is not[](4)The author[ property](5)In the last[ physics]20.As we have seen,the focus of(1)T oday medical care[ habits](2)In the first[ being ill](3)T raditionally [ disease](4)According to the author[ health](5)According to what[ limitations]21.P eople in intangible service(1)M any professionals[](2)T rust is regardes as[ or not](3)What do [ bamboozled](4)What will happen[ destroyed](5)Which of the following[ be trusted]22.S cratchy throats,stuffy noses(1)According to the author[ illness](2)We learn form[ a cold or the flu](3)According to the passage[ disease](4)Which of the[ high temperature](5)If children have[ aspirin]23.S ign has become a scientific(1)The study of[ a language](2)The present growing[ the deaf](3)According to stoke[ genuine language](4)M ost educators[ speech sounds](5)S tokoe’s argument[ the brain]24.It is hard to track the blue whale(1)The passage[ system](2)The underwater[ vessels](3)The deep-sea[ sound](4)It can be[ use](5)Which of the[ scientists]25.Y ou never see them,but(1)What does[ airplane](2)What information[ of the crash](3)Why was the black[ the crash](4)Why did[ identifiable ](5)What do we know[ recovered]26.New technology links the world(1)What is [](2)With the increased[ business](3)In the passage[ abroad](4)According to the passage[’s language](5)The advantage of[ process]27.A properly designed electrical(1)When there is[ dangerous heat](2)Want will circuit[ immediately](3)What’s the fuction[ other circuits](4)Through electrical[ outside](5)How dose a circuit[ exceed]28.E vey hour the sun beams(1)F orm the first[ technology](2)What is the percentage[ than one thousandth](3)Where can[ rooftops](4)In solar thermal[ source](5)By what[ moveable mirrors]29.Researchers say people traveling(1)The main[ air](2)Those who[ a car](3)Which of the[ vehicles](4)People living[ diseases](5)Which of[ attacks]30.decision to(1)On what[ smoking](2)The purpose of[ smoking](3)Where can[](4)Which of the[ you](5)What is the[ them]31.Unwanted sound,or noise,such(1)Noise pollution[ productivity](2)Which of the[ sound](3)Where is[ airports](4)Which sound[ hertz](5)What method[ protection]32.A smart grid incorporates(1)What can customers[ pattern](2)One of the[ energy](3)What can larger[ events](4)What can a smart[ wisely](5)Which of the following[ smart grid] 33.In economic terms,electricity(1)An electricity[ electricity](2)What is the price[ demand](3)Who will be[ operators](4)The restructuring of [ markets](5)Why is[ power pricing]34.L arge airports with lots of(1)S everal languages[ airports](2)How are the[ in](3)Which airport can [](4)Which of the[ suffer jet lag](5)If you leave[ found]35.E verybody in the city uses mobile(1)M obile phones[ places](2)What do we[ use](3)Which of the following translations[ tomorrow](4)Why does the writer[ is use](5)Which of the following is ture[ phones]36.In our country,the power grid(1)In our country[b.+](2)In the power grid[b.+60s](3)The running of[ AC single-phase synchronous motor](4)In the power grid with a capacity of 3000MW[+](5)The primary[+]37.All the useful energy at the surface(1)The sun is the [ power](2)Radiant energy[](3)The sun’s energy[](4)The largest part of[](5)Of the sun’s total[ portion]38.The market is a concept.(1)Which of the following[ is the market](2)All of [ night school](3)Y ou are buying[at a restaurant](4)The word[](5)In what way[ produce]39.Nowadays more and more people(1)Which of the[](2)According to[ crowded](3)Little cars[ life](4)A little car is[ third the size of](5)Large cars[]40.The transmission and transformation of(1)The function[ electric power](2)In our country,what[ and 220kv](3)In our country,the specified[ line…..effective value](4)What is[ ultra-high voltage](5)In our country,the voltage[ above]41.The science of meteorology is concerned(1)Which of the following is the best[…］(2)The predictions[ maps](3)Which of the following is not[](4)The author[ and property](5)In the last[]42.A friend of mine,in response(1)The author[ unfair](2)S urrendering to[ things](3)The second[ the life](4)In the last[ fair](5)F orm the[]43.The cause of the decline of north(1)What do people[ factors](2)The main[ north africa](3)Which of [ forests](4)Increase in[ it](5)F orm this []44.It is hard to track the bule whale(1)The passage[](2)The underwater[](3)The deep-sea[](4)It can be[](5)Which of[]。