宁波理工学院外语平台第四学期阅读答案

was the one field of awareness about which humans had anything more than the vaguest of insights. It is impossible to know today just what our Stone Age ancestors knew about plants, but from what we can observe of preindustrial societies that still exist, a detailed learning of plants and their properties must be extremely ancient. This is logical. Plants are the basis of the food pyramid for all living things, even for other plants. They have always been enormously important to the welfare of people, not only for food, but also for clothing, weapons, tools, dyes, medicines, shelter, and a great many other purposes. Tribes living today in the jungles of the Amazon recognize literally hundreds of plants and know many properties of each. To them botany, as such, has no name and is probably not even recognized as a special branch of "knowledge" at all. Unfortunately, the more industrialized we become the farther away we move from direct contact with plants, and the less distinct our knowledge of botany grows. Yet everyone comes unconsciously on an amazing amount of botanical knowledge, and few people will fail to recognize a rose, an apple, or an orchid. When our Neolithic（新石器时代）ancestors, living in the middle East about 10,000 years

ago, discovered that certain grasses could be harvested and their seeds planted for richer yields the next season, the first great step in a new association of plants and humans was taken. Grains were discovered and from them flowed the marvel of agriculture: cultivated crops. From then on, humans would increasingly take their living from the controlled production of a few plants, rather than getting a little here and a little there from many varieties that grew wild---and the accumulated knowledge of tens of thousands of years of experience and intimacy with plants in the wild would begin to fade away.

-------------------------------------------------------------------------------- 1. Which of the following assumptions about early humans is expressed in the passage? A . They probably had a detailed learning of plants. B . They enjoyed the study of welfare. C . They attached much importance to their property. D . They thought that cultivating crops were not important. 正确答案:They probably had a detailed learning of plants. 题目详解:根据问题中…assu mptions about early humans is expressed?的提示，从第1 段的第3 句中…a detailed learning of plants and their properties must be extremely ancient?提供的信息判断，选项中的"They

probably had a detailed learning of plants" 符合题意。2. According to the passage, why has general knowledge of botany begun to fade? A . Botany is not considered as a special branch of science. B . Direct contact with a variety of plants has decreased. C . People find it difficult to know the names of new plants. D . Plants are not longer valued as a useful resource. 正确答案:Direct contact with a variety of plants has decreased. 题目详解:依据问题中" general knowledge of botany begun to fade "的提示，从最后一段文章的最后一句中"rather than getting a little here and a little there from many varieties that grew wild"中提供的信息判断，选项中的"Direct contact with a variety of plants has decreased"符合题意。3. What does the sentence "This is logical" In Para 1, line 6 mean? A . It is hard to determine the extent of our ancestor's knowledge of plants. B . It is reasonable to assume that our ancestors behaved very much like people in pre-industrial. C . Human learning of plants is very detailed and well organized. D . It is not astonishing that early humans had a detailed knowledge of plants. 正确答案:It is not astonishing that early humans had a detailed knowledge of plants. 题目详解:依据问题中"This is logical" In Para 1, line 6"的提示，从

第1 段第4 句中的"a detailed learning of plants and their properties"中提供的信息判断，选项中的"It is not astonishing that early humans had a detailed knowledge of plants"符合题意。4. In Para 2, line 4, what is the author's purpose in mentioning "a rose, an apple, or an orchid"? A . To offer examples of plants that are more attractive. B . To give botanical examples that all readers will recognize. C . To make the passage more vivid and poetic. D . To show the diversity of botanical life. 正确答案:To give botanical examples that all readers will recognize. 题目详解:根据问题中的"a rose, an apple, or an orchid"的提示，从第 2 段第2 句中" Yet everyone comes unconsciously on an amazing amount of botanical knowledge, and few people will fail to recognize " 提供的信息判断，选项中的"To give botanical examples that all readers will recognize"符合题意。5. The relationship between botany and agriculture is similar to the relationship between zoology (the study of animals) and ______. A . horseback riding B . bird watching C . deer hunting D . sheep raising 正确答案:sheep raising 题目详解:根据问题中…The relationship between botany and agriculture is similar to?的提示。从最后一段文章倒数第2 句中" Grains were discovered and from them flowed the

marvel of agriculture: cultivated crops " 提供的信息判断，选项中的"sheep raising" 符合题意。Nuclear power plants provide about 17 percent of the world's electricity. Some countries depend more on nuclear power for electricity than others. In France, for instance, about 75 percent of the electricity is generated from nuclear power, according to the International Atomic Energy Agency. In the United States, nuclear power supplies about 15 percent of the electricity overall, but some states get more power from nuclear plants than others. There are more than 400 nuclear power plants around the world, with more than 100 in the United States. Have you ever wondered how a nuclear power plant works or how safe nuclear power is? In this article, we will examine how a nuclear reactor and a power plant work. Uranium Uranium is a fairly common element on Earth, which was taken into the planet during the planet's formation. Uranium is originally formed in stars. Old stars exploded, and the dust from these shattered stars aggregated together to form our planet. Uranium-238

(U-238) has an extremely long life (4.5 billion years) , and therefore is still present in fairly large quantities. U-238 makes up 99 percent of the uranium on the planet. U-235

makes up about 0. 7 percent of the remaining uranium found naturally, while U-234 is even rarer and is formed by the decay of U-238. Nuclear Fission (裂变) A nuclear fission happens when a uranium-235 nucleus with a neutron captures another neutron. The nucleus then splits into two lighter atoms and throws off two or three new neutrons (the number of ejected neutrons depends on how the

U-235 atom happens to split). The two new atoms then produce gamma radiation as they settle into their new states. There are three things about this induced fission process that make it especially interesting: ? The probability of a U-235 atom capturing a neutron as it passes by is fairly high. In a reactor working properly (known as the critical state), one neutron ejected from each fission causes another fission to occur. ? The process of capturing the neutron and splitting happens very quickly, on the order of picoseconds (1 xlO-2 seconds). ? An incredible amount of energy is released, in the form of heat and gamma radiation, when a single atom splits. The two atoms that result from the fission later release beta radiation and gamma radiation of their own as well. The energy released by a single fission comes from the fact that

the fission products and the neutrons, together, weigh less than the original U-235 atom. The difference in weight is converted directly to energy at a rate governed by the equation E = mc. In order for these properties of U-235 to work, a sample of uranium must be enriched so that it contains 2 percent to 3 percent or more of uranium-235. Three-percent enrichment is sufficient for use in a civilian nuclear reactor used for power generation. Weapons-grade uranium is composed of 90-percent or more U-235. Inside a Nuclear Power Plant To build a nuclear reactor, what you need is some mildly enriched uranium. Typically, the uranium is formed into pellets (芯块) with approximately the same diameter as a coin and a length of an inch or so. The pellets are arranged into long rods, and the rods are collected together into bundles. The bundles are then typically submerged in water inside a pressure vessel. The water is used to lower the heat. In order for the reactor to work, the bundle, submerged in water, must be slightly supercritical. That means that, left to its own devices, the uranium would eventually overheat and melt. To prevent this, control rods (棒) made of a material that absorbs neutrons are inserted into the bundle. Raising and lowering

the control rods allow operators to control the rate of the nuclear reaction. When an operator wants the uranium core to produce more heat, the rods are raised out of the uranium bundle. To create less heat, the rods are lowered into the uranium bundle. The rods can also be lowered completely into the uranium bundle to shut the reactor down in the case of an accident or to change the fuel. The uranium bundle acts as an extremely high-energy source of heat. It heats the water and turns it to steam. The steam drives a steam turbine, which spins a generator to produce power. In some reactors, the steam from the reactor goes through a secondary, intermediate heat exchanger to convert another loop of water to steam, which drives the turbine. Outside a Nuclear Power Plant Once you get past the reactor itself, there is very little difference between a nuclear power plant and a coal-fired or oil-fired power plant except for the source of the heat used to create steam. The reactor's pressure vessel is typically housed inside a concrete liner that acts as a radiation shield. That liner is housed within a much larger steel containment vessel. This vessel contains the reactor core as well the hardware that allows workers at the plant to refuel and maintain the

reactor. The steel containment vessel is intended to prevent leakage of any radioactive gases or fluids from the plant. Finally, the containment vessel is protected by an outer concrete building that is strong enough to survive such things as crashing jet airliners. These secondary containment structures are necessary to prevent the escape of radiation/radioactive steam in the event of an accident like the one at Three Mile Island. The absence of secondary containment structures in Russian nuclear power plants allowed radioactive material to escape in an accident at Chernobyl. What Can Go Wrong Well-constructed nuclear power plants have an important advantage when it comes to electrical power generation - they are extremely clean. Compared with a coal-fired power plant, nuclear power plants are a dream come true from an environmental standpoint. A coal-fired power plant actually releases more radioactivity into the atmosphere than a properly functioning nuclear power plant. Coal-fired plants also release tons of carbon, sulfur and other elements into the atmosphere. Unfortunately, there are significant problems with nuclear power plants; ? Mining and purifying uranium has not, historically, been a very clean process. ?

Improperly functioning nuclear power plants can create big problems. The Chernobyl disaster is a good recent example. ? Spent fuel from nuclear power plants is toxic (有毒的) for centuries, and, as yet, there is no safe, permanent storage facility for it. ? Transporting nuclear fuel to and from plants poses some risk, although to date, the safety record in the United States has been good. These problems have largely derailed the creation of new nuclear power plants in the United States. Society seems to have decided that the risks outweigh the rewards.

-------------------------------------------------------------------------------- 1.There are over 400 nuclear power plants in the world, most of which are in Europe. A.Y B.N C.NG 正确答案:NG 题目详解:该句的句意为：世界上有400 多个核电站，其中大多数在欧洲。从文章的第一段的最后一句话，我们

知道全球有四百多个核电站，其中100 多个核电站在美国，但是我们并不知道欧洲的核电站有两百多个 2.Scientists believe that uranium was absorbed by the Earth when it was formed. A.Y B.N C.NG 正确答案:Y 题目详解:该句的句意为：科学家相信在地球形成之时就已经吸收了铀，在“Uranium”一节中，我们得知铀原来形成于其他的星球，地球在形成之前将这种元素吸收了过来。 3. The German

government has decided to reduce its dependence on electricity generated by nuclear power. A.Y B.N C.NG 正确答案:NG. 题目详解:该句的句意为：德国政府已经决定减少对核电的依赖.文章没有提到德国对核电的态度，更没有说德国政府要减少对核电的依赖. 4.A nuclear fission is a process of a U-235 nucleus with a neutron trying to capture another neutron. A.Y B.N C.NG 正确答案:Y 题目详解:该句的句意为：核裂变的过程是带有一个中子的U-235 核捕捉另一个中子，在“Unclear Fession”一节。文章解释核裂变的过程就是带有一个中子的U-235 核捕捉另一个中子。

5.Uranium has to be enriched if a nuclear reactor is built.

A.Y

B.N

C.NG 正确答案:Y 题目详解:该句的句意为：如果要建立一个核反应堆必须要有浓缩铀. 6.Control rods in a nuclear reactor are used to control the amount of energy generated in a nuclear reactor. They can also be used to shut the reactor or to change the fuel. A.Y B.N C.NG 正确答案:Y 题目详解:该句的句意为：核反应堆中的控制棒是用来控制核反应堆所释放的能量，而且也可以用来关闭核反应堆释放的能量，调换核燃料，或关闭核反应堆。7.Mining and purifying uranium do not cause any environmental damage. A.Y B.N C.NG 正确答案:N 题目详解:该句的句意为：在开采和提纯铀时的不会对环境造成破坏。在“What

Can Go Wrong”一节中，文章说明铀的开采和提纯一直不是一个很干净的过程，意思是铀的开采和提纯会污染环境。

8.A nuclear reactor is protected by __________________,

a concrete radiation shield, a steel containment vessel, and an outer concrete building. 正确答案:a pressure vessel 题目详解:该句的句意为：核反应堆的保护装置有一个压力容器层，一个水泥(防)辐射层，一个钢板容器层和一个外层水泥容器层，在“Outside a Nuclear Power Plant”中，我们得知为了确保安全，核反应堆有四层保护：压力容器层，水泥辐射层，钢板容器层和外层水泥容器层。9.The result of nuclear fission is to release energy in the form of_______. 正确答案:heat and gamma radiation. 题目详解:“Unclear Fession”的第三点就是介绍核裂变的结果是释放热量和伽马辐射。10.The present solution to dispose _______is yet to be found as it remains toxic for a fairly long time. 正确答案:spent fuel 或spent nuclear fuel. 题目详解:在“What Can Go Wrong”一节中，作者提到核废料的毒性会持续数百年，现在没有一个安全而永久的设施可以储存核废料。In the United States, when you get your paycheck at the end of the first pay period at a new job, it's always interesting to see your net pay. Most of us expect more than we get. By the time you get your check, it has been cut up like a pizza,

with several entities taking a piece of the pie. The entities that take money differ from person to person, company to company and state to state. However, almost every income earner has to pay federal income tax. Taxes in Early America Taxes have always left a sour taste in the mouth of American citizens. This national hatred for taxes dates back to the tax burden placed on the American colonies by Great Britain. Colonists were taxed for every consumer goods, from tea and tobacco to legal documents. This "taxation without representation" led to many revolts, such as the Boston Tea Party, in which colonists dumped tea into the Boston Harbor rather than pay the tax on it. Although the American colonists fought for independence from British rule and British taxes, once the United States government formed, its main source of revenue was derived from placing customs and excise taxes on the same items that were taxed by Great Britain. In 1812, in an effort to support an expensive war effort, the U. S. government imposed the first sales tax, which was placed on gold, silverware, jewelry and watches. In 1817, internal taxes were terminated and the government relied on tariffs to support