智慧树慕课答案
1、填空题：
Read the text in Unit 3 and find at least three examples of metaphorical expressions.
答案: 【 Title: odyssey years
Para. 3: a solid idea of childhood
Para. 5: frame their concept of adulthood
Para. 6: saddle young people with enormous pressure;
the fluid journey of discovery
Para. 10: grow more pronounced in the coming years】点我阅读全文
1、单选题：
下面是私有 IPv4 地址块的是
选项：
A: 10.0.0.0 到 10.255.255.255
B: 169.254.0.0 到 169.254.255.255
C: 192.0.2.0 到 192.0.2.255
D: 240.0.0.0 到 255.255.255.254
答案: 【 10.0.0.0 到 10.255.255.255】点我阅读全文
1、单选题：
东方式插花的代表国家
选项：
A: 中国和日本
B: 中国
C: 印度
D: 韩国
答案: 【 中国和日本】点我阅读全文
1、单选题：
“营养”一词中“营”的意思是：
选项：
A: 养生
B: 食物
C: 有益
D: 谋求
答案: 【 谋求】点我阅读全文
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
1、单选题：
世界上第一台数字式电子计算机的名字叫 。
选项：
A: EDVAC
B: ENIAC
C: EDSAC
D: UNIVAC
答案: 【 ENIAC】点我阅读全文
1、单选题：
狭义的电子商务的英文表达是：
选项：
A: Electronic Commerce
B: Electronic Business
C: Electronic Government
D: Electronic Banking
答案: 【 Electronic Commerce】点我阅读全文
1、单选题：
以下关于独立站的描述，哪一条是准确的？
选项：
A: 在国内，大家都使用独立站在网上购买商品
B: 独立站的内容对付费搜索广告没有影响，只要购买关键字就好了
C: SEO是独立站免费流量的来源之一，用户搜索结果页面展示位置在付费广告的下面
D: 以上皆非
答案: 【 SEO是独立站免费流量的来源之一，用户搜索结果页面展示位置在付费广告的下面】点我阅读全文
1、单选题：
绝对购买力平价理论认为两种货币间的汇率决定于（ ）
选项：
A: 法定平价
B: 两国货币购买力的变动
C: 两国货币在各自国内的购买力之比
D: 铸币平价
答案: 【 两国货币在各自国内的购买力之比】点我阅读全文
