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字符串习题

1、单选题：

​执行下列代码后，结果字符串的值是？ 

‍选项：
A: HelloldAgain
B: Wor
C: Hello d Again
D: Worl 
答案: 【 Worl 】点我阅读全文

第一章测验题

1、单选题：
‍管理思想史发展过程中，用来说明“职业”管理角色最古老的是（  ）‍
选项：
A: 法老
B: 宰相
C: 大臣
D: 皇帝
答案: 【 宰相】点我阅读全文

第一章单元测验

1、单选题：
​单就电动机拖动而言，它的发展在大体上经历了              、               和                三个阶段。‍
选项：
A: 成组拖动、单电机拖动（和）多电机拖动
B: 单电机拖动、成组拖动（和）多电机拖动
C: 单电机拖动、多电机拖动（和）成组拖动
D: 单电机拖动、成组拖动（和）多电机拖动
答案: 【 成组拖动、单电机拖动（和）多电机拖动】点我阅读全文

第二章测验

1、单选题：
‏各物体被移动后，其形象还能在视网膜上停留（  ）​
选项：
A: 1/12秒
B: 1/24秒
C: 1/36秒
D: 1/48秒
答案: 【 1/24秒】点我阅读全文

1.1测验

1、判断题：
‎翻译就是指翻译行为。​
选项：
A: 正确
B: 错误
答案: 【 错误】点我阅读全文

第2讲-小测验

1、单选题：
‏以下不能对二维数组a进行正确初始化的语句是‍
选项：
A: int a[2][3]={0};
B: int a[][3]={{1,2},{0}};
C: int a[][3]={1,2,3,4,5,6};
D: int a[2][3]={{1,2},{3,4},{5,6}};
答案: 【 int a[2][3]={{1,2},{3,4},{5,6}};】点我阅读全文

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

第一章测验 矢量分析

1、单选题：
​两个非零矢量点积为零，说明这两个矢量‎
选项：
A: 平行
B: 垂直
C: 共面
D: 相交
答案: 【 垂直】点我阅读全文

第一次中期测验

1、单选题：
‏价值观的作用不包括哪个选项？‌
选项：
A: 胶水作用
B: 地基作用
C: 尺子作用
D: 增速作用
答案: 【 增速作用】点我阅读全文

单元测验1

1、单选题：
‎有大小不同的两个地球仪，两者相比，则（   ）‍
选项：
A: 两个地球仪的比例尺一样大
B: 大地球仪的比例尺比较大
C: 小地球仪的比例尺比例尺大
D: 大地球仪表示的实际范围大
答案: 【 大地球仪的比例尺比较大】点我阅读全文