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第一章操作系统概述

1.1-1.3测试

1、单选题：
​下列观点中，不是描述操作系统的典型观点是（）‍
选项：
A: 操作系统是众多软件的集合
B: 操作系统是用户和计算机之间的接口
C: 操作系统是资源的管理者
D: 操作系统是虚拟机
答案: 【 操作系统是众多软件的集合】点我阅读全文

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项目1认识PLC

1-1随堂测验

1、单选题：
‏PLC的实际应用中，哪些不属于开关量逻辑控制？‌
选项：
A: 注塑机控制
B: 电镀生产线
C: 电梯控制
D: 温度、压力、流量等连续变化的模拟量的闭环控制
答案: 【 温度、压力、流量等连续变化的模拟量的闭环控制】点我阅读全文

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Lesson 2

Scanning

1、单选题：
‏Read the passage "The Discovery of X-rays" quickly and choose the paragraph(s) which contain(s) the answer(s). You may choose more than one answer for question 3. ‏‏‏The Discovery of X-rays‏‏ ‏Par. 1 Except for a brief description of the Compton effect, and a few other remarks, we have postponed the discussion of X-rays until the present chapter because it is particularly convenient to treat X-ray spectra after treating optical spectra. Although this ordering may have given the reader a distorted impression of the historical importance of X-rays, this impression will be corrected shortly as we describe the crucial role played by X-rays in the development of modern physics.‏Par. 2 X-rays were discovered in 1895 by Roentgen while studying the phenomena of gaseous discharge. Using a cathode ray tube with a high voltage of several tens of kilovolts, he noticed that salts of barium would fluoresce when brought near the tube, although nothing visible was emitted by the tube. This effect persisted when the tube was wrapped with a layer of black cardboard. Roentgen soon established that the agency responsible for the fluorescence originated at the point at which the stream of energetic electrons struck the glass wall of the tube. Because of its unknown nature, he gave this agency the name X-rays. He found that X-rays could manifest themselves by darkening wrapped photographic plates, discharging charged electroscopes, as well as by causing fluorescence in a number of different substances. He also found that X-rays can penetrate considerable thicknesses of materials of low atomic number, whereas substances of high atomic number are relatively opaque. Roentgen took the first steps in identifying the nature of X-rays by using a system of slits to show that (1) they travel in straight lines, and that (2) they are uncharged, because they are not deflected by electric or magnetic fields.‏Par. 3 The discovery of X-rays aroused the interest of all physicists, and many joined in the investigation of their properties. In 1899 Haga and Wind performed a single slit diffraction experiment with X-rays which showed that (3) X-rays are a wave motion phenomenon, and, from the size of the diffraction pattern, their wavelength could be estimated to be 10-8 cm. In 1906 Barkla proved that (4) the waves are transverse by showing that they can be polarized by scattering from many materials.‏Par. 4 There is, of course, no longer anything unknown about the nature of X-rays. They are electromagnetic radiation of exactly the same nature as visible light, except that their wavelength is several orders of magnitude shorter. This conclusion follows from comparing properties 1 through 4 with the similar properties of visible light, but it was actually postulated by Thomson several years before all these properties were known. Thomson argued that X-rays are electromagnetic radiation because such radiation would be expected to be emitted from the point at which the electrons strike the wall of a cathode ray tube. At this point, the electrons suffer very violent accelerations in coming to a stop and, according to classical electromagnetic theory, all accelerated charged particles emit electromagnetic radiations. We shall see later that this explanation of the production of X-rays is at least partially correct.‏Par. 5 In common with other electromagnetic radiations, X-rays exhibit particle-like aspects as well as wave-like aspects. The reader will recall that the Compton effect, which is one of the most convincing demonstrations of the existence of quanta, was originally observed with electromagnetic radiation in the X-ray region of wavelengths.‏‏‏‏When were X-rays discovered?‏
选项：
A: Par. 1
B: Par. 2
C: Par. 3
D: Par. 4
E: Par. 5
答案: 【 Par. 2】点我阅读全文

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第一周 第二周 第一专题 天涯何处是神州

第一专题综合测验题

1、单选题：
‎从1793年马戛尔尼使华事件可以看出，清王朝在（  ）皇帝在位时期已开始走向衰落。‌
选项：
A: 嘉庆
B: 乾隆
C: 雍正 
D: 道光
答案: 【 乾隆】点我阅读全文

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学习情境1 发动机综合性能检测

学习情境1 测验

1、单选题：
‍过高的击穿电压预示着(     )故障。‏
选项：
A: 高压线开路
B: 火花塞结炭
C: 高压线短路
D: 火花塞瓷绝缘开裂
答案: 【 高压线开路】点我阅读全文

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第1讲 教育统计概述与SPSS简介

第一章 SPSS简介测验题

1、单选题：
‏SPSS数据文件的扩展名是（    ）。‏
选项：
A: .xls
B:  .sav
C: .spv
D:  .dbf
答案: 【  .sav】点我阅读全文

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Week 1 Designing pronunciation activities

NEW Quiz 1

1、单选题：
‌Which of the following is NOT the reason why we teach pronunciation?‎
选项：
A: Pronunciation is the most important part in any language learning process.
B: Good pronunciation is always important for students to achieve effective communication.
C: To improve intelligibility in communication is one major reason for teaching pronunciation.
D: Teaching pronunciation can also help students in other aspects of English learning.
答案: 【 Pronunciation is the most important part in any language learning process.】点我阅读全文

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第1章外币折算

1.1外币、外汇、记账本位币和列报货币随堂测试题

1、单选题：
‍下列各项中，企业应选择人民币为记账本位币的是（　　）‎
选项：
A: 甲公司为外贸自营出口企业，超过80%的营业收入来自对美国的出口，其商品销售价格主要受美元的影响，以美元计价
B: 乙公司除厂房设施、30%的人工成本在国内以人民币采购或支付外，生产所需原材料、机器设备及70%以上的人工成本都以美元采购或支付
C: 丙公司95%以上的人工成本、原材料及相应的厂房设施、机器设备等在国内采购并以人民币计价，甲公司取得的美元营业收入在汇回国内时直接兑换成了人民币存款
D: 丁公司为国内某大型企业在美国的子公司，以美元核算，丁公司在境外产生的现金流量在该大型企业不提供资金的情况下，可以偿还现有债务和正常情况下可预期的债务
答案: 【 丙公司95%以上的人工成本、原材料及相应的厂房设施、机器设备等在国内采购并以人民币计价，甲公司取得的美元营业收入在汇回国内时直接兑换成了人民币存款】点我阅读全文

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第1章磁路

第1单元测试

1、单选题：
 在电能的传输中主要用到电机学中的（）。​‌​
选项：
A: 交流发电机
B:   变压器  
C: 交流电动机  
D: 直流电动机
答案: 【   变压器  】点我阅读全文

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