Part Ⅱ Reading Comprehension (Skimming and Scanning)
Directions: In this part, you will have 15 minutes to go over the passage quickly.
   Y (for YES)  if the statement agrees with the information given in the passage;
   N(for NO)  if the statement contradicts the information given in the passage;
   NG(for NOT GIVEN)  if the information is not given in the passage.
   For questions 8 -10, complete the sentences with information given in the passage.

    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 ( 1×10¹²seconds).
    ·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 = mc2.
    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 hundred nuclear power plants in the world, most of the them are in Europe.

  

NG

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，我们知道全球有四百多个核电站，其中100个核电站在美国，但是我们并不知道欧洲的核电站有二百多个。

 

2.  Scientists believe that uranium was absorbed by the Earth when it was formed.

  

Y

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，我们得知铀原来形成于其他的星球，地球在形成时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.

  

NG

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.

  

Y

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“Nuclear Fission”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.

  

Y

该句的句意为：如果要建立一个核反应堆，必须要对铀进行浓缩。在“Insider a Nuclear Power Plant”一节中，作者介绍建立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.

  

Y

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更换燃料。从“Insider a Nuclear Power Plant”一节中，我们得知燃料控制棒的功能是：调节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.

  

N

该句的句意为：在开采和提纯铀时的确会对环境造成破坏。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.

  

a pressure vessel

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。
a pressure vessel．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。因此，答案应该是a pressure vessel。

 

9.  The result of nuclear fission is to release energy in the form of ______.

  

heat and gamma radiation．

“Nuclear Fission”的第三点就是介绍核裂变的结果是释放热量和伽马和辐射。

 

10.  The present solution to dispose ______ is yet to be found as it remains toxic for a fairly long time.

  

spent fuel或spent nuclear fuel．

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。

 

Passage One
   Noses have their advantages. They're cute, they're versatile, and they're small enough to be carried around. Which may be why the artificial odor detectors that engineers have been building since the 1950's to try to mimic the olfactory(嗅觉的) abilities of our built-in sensors have taken so long to find their way to the market--and then, in most cases, have flopped(失败).
   But things are finally looking up for the electronic nose. Thanks to advances in chip technology and pattern-recognition techniques, increasingly tiny sniffers (嗅探器) are beginning to live up to their moniker (模仿者)- Today e-noses are being tested for everything from disease detection to disaster prevention, and lower-prices models are starting to come to the market including an $ 8,000 device called the Cyranose 320 being introduced this week by Cyrano Sciences of Pasadena, Calif.
   Like our proboscises(长鼻子), e-noses are only as good as their sensors, and all of them operate on oiliness(油质)--rather than to the molecule itself. Working together, the receptors can generate unique principles remarkably similar to those of a real nose. Humans detect odors with up to 650 types of receptors found on cells high up in the nasal passages, somewhere between our eyebrows. How the nose works is still something of a mystery, but it is believed that each receptor responds to a subtle characteristic of a molecule that carries odor--its peculiar shape, say, or degree of "smell prints" of a wide variety of odors, which are then parceled off to the brain and stored.
   In e-noses, chemical sensors replace the body's cellular receptors, and microprocessors substitute for the brain. "What limits these devices is how well the sensors are doing," explains Nathan Lewis, the Caltech chemist who helped invent the sensor technology licensed by Cyrano and who has since continued his research independently. He compares the power of e-noses to the resolution of computer monitors: "Are you seeing the world in eight shades of gray or in 16 million colors?"

    Noses have their advantages. They're cute, they're versatile, and they're small enough to be carried around. Which may be why the artificial odor detectors that engineers have been building since the 1950's to try to mimic the olfactory(嗅觉的) abilities of our built-in sensors have taken so long to find their way to the market--and then, in most cases, have flopped(失败).
    But things are finally looking up for the electronic nose. Thanks to advances in chip technology and pattern-recognition techniques, increasingly tiny sniffers (嗅探器) are beginning to live up to their moniker (模仿者)- Today e-noses are being tested for everything from disease detection to disaster prevention, and lower-prices models are starting to come to the market including an $ 8,000 device called the Cyranose 320 being introduced this week by Cyrano Sciences of Pasadena, Calif.
    Like our proboscises(长鼻子), e-noses are only as good as their sensors, and all of them operate on oiliness(油质)--rather than to the molecule itself. Working together, the receptors can generate unique principles remarkably similar to those of a real nose. Humans detect odors with up to 650 types of receptors found on cells high up in the nasal passages, somewhere between our eyebrows. How the nose works is still something of a mystery, but it is believed that each receptor responds to a subtle characteristic of a molecule that carries odor--its peculiar shape, say, or degree of "smell prints" of a wide variety of odors, which are then parceled off to the brain and stored.
    In e-noses, chemical sensors replace the body's cellular receptors, and microprocessors substitute for the brain. "What limits these devices is how well the sensors are doing," explains Nathan Lewis, the Caltech chemist who helped invent the sensor technology licensed by Cyrano and who has since continued his research independently. He compares the power of e-noses to the resolution of computer monitors: "Are you seeing the world in eight shades of gray or in 16 million colors?"

1.  It can be learned from the passage that ______.

• A.the artificial noses are even better than the human noses
• B.it has not taken long for the artificial noses to be introduced to the market
• C.the attempts of the artificial noses to imitate the olfactory abilities have been largely unsuccessful
• D.the artificial noses have their own advantages over the human noses

  A  B  C  D  

C

细节理解题。该题问从文章中可得知什么，实际上浏览选择项，可以断定问的是关于“人工鼻子”即“the artificial odor detectors”(人造气味探测器)的问题。此题涉及到第一段第三句话中的非限制性定语从句的理解“which may be why…have flopped”(这大概是工程人员自20世纪五十年代起一直制造的人工气味探测器，力图模仿我们内嵌的感应器的嗅觉功能和花费了如此长的时间才打入市场——并且在多数情况下失败了的原因。)因此选项C是正确答案。

 

2.  Which of the following is closest in meaning to the phrase "looking up" (Line 1, Para. 2)?

• A.Raising one's eyes.
• B.Turning better.
• C.Searching for.
• D.Paying a visit.

  A  B  C  D  

B

语义题。该题测的是对常见短语look up在特定的语境中的准确理解。此处的意思是“有所改善”，正确答案是B。

 

3.  According to the passage, more and more tiny e-noses are meeting the requirements of human noses because of ______.

• A.improvements in chip technology and pattern-recognition techniques
• B.disease detection and disaster prevention
• C.expensive prices and prompt introduction of the models
• D.improvements in the olfactory abilities of our built-in sensors

  A  B  C  D  

A

细节理解题。该题问“越来越多的微小的电子鼻达到人鼻的要求”的原因是什么。根据文章第二段第二句话“Thanks to advances in chip technology and pattern-recognition techniques…”(由于晶片技术和图形识别技术方面的进步)，可断定A项为正确答案。

 

4.  It can be inferred from the passage that ______.

• A.scientists have discovered the working mechanism of the nose
• B.humans detect odors with a large number of receptors responsive to the odorous molecules themselves
• C.the receptors integrate various responses to the characteristics of an odor and store them in the brain
• D.e-noses operate on principles totally different from those of a real nose

  A  B  C  D  

C

推论题。该题问及人鼻的嗅觉原理。根据文章第三段的最后一句“How the nose works is still something of a mystery，but it is believed that．．．which are then parceled off to the brain and stored．” (鼻子的工作原理仍然是个谜：所知甚少，但是大家认为，每个接收器对具有特定形状的分子的微妙特点作出反应，或者是对众多气味的“气味痕”的程度作出反应，而这些印痕则被汇集起来，传送到大脑存贮。)因此可推出选项C为正确答案。

 

5.  The purpose of the writer in writing the passage is ______.

• A.to give an objective account of the e-nose
• B.to question the wide use of the e-nose
• C.to discuss the advantages of the e-nose over the human nose
• D.to encourage the introduction of the e-nose to the market at a lower price

  A  B  C  D  

A

主旨题。该题问及这篇文章的写作目的。对于此类的科(普)技文章，考生可以判定客观性 (objective)是惟一的标准，从而做出正确的判断。答案为A“对电子鼻做一客观报道。”