题目
题型：不详难度：来源：
In their experiment, Johnson and his team studied the “pleasure center” of rats’ brains. The pleasure center is a complicated network of nerve cells. If the animal exercises or eats, the cells reward the animal by releasing chemicals into the body that make it feel good. And when the body feels good, the animal – or person – will want to do the behavior again.
For the experiment, Johnson fed foods like cheesecake to one group of rats. Food like this is high in calories and fat. Another group of rats got a regular diet. The rats that ate junk food started to eat more and more.
“They’re taking in twice the amount of calories as the control rats,” says Paul Kenny, one of Johnson’s colleagues.
Kenny and Johnson wanted to know what was going on in the brains of these rats. They first designed a way to deliver a small electrical charge to the rats’ brains. This electrical charge would stimulate the pleasure centers to release pleasure-causing chemicals. The rats could control how much stimulation – and how much pleasure – they received by running on a wheel. The more the rat ran, the more pleasure it received.
The rats that had been eating junk food started running more and more. This behavior suggested that the junk-food-eating rats needed more brain stimulation to feel good compared with rats on a normal diet. In other words, their pleasure centers were becoming less sensitive and the junk food didn’t make them feel good unless they ate more and more.
Experiments like this one could help scientists understand how chemicals in the brain contribute to obesity. With that information, they may be able to help people avoid obesity in the first place.
(Note: Answer the questions or complete the statements in NO MORE THAN TEN WORDS.)
小题1: The scientists suggested it was actually ___________________ that made the rats feel good.
小题2: How did the scientist know what was happening in the brains of the junk-food-eating rats?
小题3:What was the purpose of the experiment mentioned in the article?
答案
小题1:chemicals in the brain
小题2: By delivering a small electrical charge to the rats’ brains.
小题3:To understand how chemicals in the brain contribute to obesity.
解析
试题分析：本文主要叙述的是一项研究，研究人脑中的化学物质是如何控制我们的行为的，尤其是如何控制我们的肥胖的。
小题1:chemicals in the brain
细节题。根据第二段2,3行If the animal exercises or eats, the cells reward the animal by releasing chemicals into the body that make it feel good.可知正是老鼠释放的化学物质让它感觉很好。
小题2: By delivering a small electrical charge to the rats’ brains.
细节题。根据文章第五段2,3行They first designed a way to deliver a small electrical charge to the rats’ brains. This electrical charge would stimulate the pleasure centers to release pleasure-causing chemicals.可知他们向老鼠的大脑里投放了一定数量的化学物质。以此来研究具体的反应。
小题3: To understand how chemicals in the brain contribute to obesity.
推理题。根据文章主体段第一段最后2行Johnson said the experiment shows that the brain chemistry of obesity(肥胖) and drug addiction may be quite similar.可知这个研究的目的在于理解头脑中的化学物质是如何导致我们的肥胖的。
核心考点
试题【The scientists observed that the more junk food the rats ate, the more they want】；主要考察你对题材分类等知识点的理解。[详细]
举一反三
Adam Kraus, of the University of Hawaii’s Institute for Astronomy, said the planet is being formed out of dust and gas circling a 2-million-yea-old star about 450 light years from Earth.
The planet itself, based on scientific models of how planets form, is believed to have started taking shape about 50,000 to 100,000 years ago.
Called LkCa 15b, it’s the youngest planet ever observed. The previous record holder was about five times older.
Kraus and his colleague, Michael Ireland from Macquarie University and the Australian Astronomical Observatory, used Keck telescopes on Mauna Kea(a volcano on the island of Hawaii, US) to find the planet. Kraus presented the discovery Wednesday at NASA’s Goddard Space Flight Center in Maryland.
Observing planets while they’re forming can help scientists answer questions like weather planets form early in the life of a star or later, and whether they form relatively close to stars or father away.
Planets can change orbits(轨道) after forming, so it’s difficult to answer such questions by studying older planets.
“These very basic questions of when and where are best answered when you can actually see the planet forming, as the process is happening right now,” Kraus said.
Scientists hadn’t been able to see such young planets before because the stars they’re circling around outshine(光亮强过) them. Kraus and Ireland used two techniques to overcome this problem.
One method, which is also used by other astronomers, was to change the shape of the telescope mirrors to remove light distortion(扭曲) created by the Earth’s atmosphere. The other method they used, which was unique, was to put masks with several holes over most of the telescope mirrors. The combination of these techniques allowed the astronomers to obtain high-quality images that let them see the planet next to the bright star.
The star LkCa 15—the planet is named after its star—was the team’s second target. They immediately knew they were seeing something new, so they plan to gather more data on the star.
小题1:The research on younger planets helps scientists _____________.
| A．study why planets change orbits after forming |
| B．understand how planets move around their stars |
| C．answer questions about the age of stars and planets |
| D．know the relationship between planets and their stars |
| A．Their stars are brighter than them.. | B．They are very far from the earth. |
| C．They are generally too small. | D．They rarely form. |
| A．have been working in the same university |
| B．observed the planet on a volcano in Hawaii |
| C．used two new methods in the observation |
| D．cut holes in the mirrors when observing |
| A．Youngest planet seen as it’s forming. |
| B．Planet 450 light years away discovered. |
| C．World’s first direct image of a planet taken. |
| D．New technique helps discover young planets. |
Koala bears are one of the most lovely Australian animals. In certain cases where the koala has been raised by hand, they have turned out to be quite affectionate pets. These people tied a piece of fur to a pillow and placed it beside a joey (a baby kola) as a substitute (替代物) for the mother koala. This trick seemed to work well with the baby koala. However, it is a known fact that human handling causes stress to koalas. In my personal opinion, this aspect clouds the fact that koala bears can be tamed (驯服).
In Australia the koala is a priority animal as far as conservation status assessment is concerned. It was hunted to near extinction (灭绝) for its fur. In fact the koala had been wiped out from South Australia in the 1920s. However, rehabilitation efforts have brought the animal back in the state. As for the Australia government, the koala is not a threatened animal, but the US government does list the koala as one.
Although they may live in 40 to 60 kinds of eucalyptus trees, they prefer only 10 to 14 specific kinds. Koalas sleep for most part of the day, which is about 16 to 18 hours, and for most of their waking hours all they do is eat. Koala bears eat the leaves of eucalyptus trees. A full-grown koala can eat almost 2 to 3 pounds of leaves in a day. Despite their slow movements and sweet look, koala bears can be vicious when hungry. Other than this, there are the stress caused to koalas due to human handling and the fights that start in koalas.
Almost everyone finds koalas lovely in the zoo. However, as far as having koala bears as pets is concerned, there are legal issues to consider. Other than that, being able to provide for its diet and habitat is another point that needs some attention before any law legalizing their adoption as pets is passed.
小题1:What’s the author’s attitude towards people raising the koala?
| A．Optimistic. | B．Grateful. | C．Cautious. | D．Enthusiastic. |
| A．To get its fur. | B．To eat its meat. | C．To wipe it out. | D．To have it for fun. |
| A．fierce and dangerous | B．patient and friendly |
| C．afraid and defensive | D．lovely and interesting |
| A．koala bears tend to live in groups |
| B．koala bear care can be very demanding |
| C．koala bears are not particular about their food |
| D．koala bears are the No. 1 threatened animal in the US |
One cost-cutting proposal is to allow college students to get a bachelor’s degree in three years instead of four. Educational institutions have been actively exploring ways to make the learning process more efficient. But there’s a question: Would the quality of undergraduate(本科生)education suffer? Few US universities have formally approved a “three-year degree” model.
I doubt that mainstream North American colleges will carry out a three-year curriculum(课程) any time soon. For one thing, most universities already allow highly qualified students to graduate early by testing out of certain classes and obtaining a number of college credits(学分). In addition, at famous universities, the committee who determine which courses are required and which courses are electives are unlikely to suddenly “throw out” one quarter of the required credits. Professors will resist “diluting(稀释)” the quality of the education they offer.
In my opinion, a quality four-year education is always superior to a quality three-year education. A college education requires sufficient time for a student to become skilled in their major and do coursework in fields outside their major. It is not a good idea to water down education, any more than it’s not a good idea to water down medicine. If we want to help students find their way through university, we should help them understand early on what knowledge and skills they need to have upon graduation. We should allow students to test out of as many courses as possible. We should give them a chance to earn money as interns(实习生)in meaningful part-time jobs that relate to their university studies, such as the five-year co-op program at Northeastern University.
小题1:The first paragraph serves as a(n)________．
| A．explanation | B．definition | C．introduction | D．comment |
| A．most American universities are against the “three-year degree” model |
| B．many famous US universities are considering adopting the “three-year degree” model |
| C．professors are willing to accept the “three-year degree” model |
| D．the “three-year degree” model can make college learning more efficient |
| A．college students are offered the co-op program |
| B．electives’ credits make up one quarter of the required credits |
| C．all students are required to finish four-year education before graduation |
| D．some excellent students can graduate ahead of time |
| A．the author is a college professor |
| B．the author thinks the cost of a university education is too high for people to afford |
| C．the author considers the university education quality very important |
| D．the author pays special attention to the all-round development of college students |
| A．It’s time to shorten the learning process |
| B．Best learning takes place over time |
| C．University education should be watered down |
| D．College education calls for reform |
Remember these three _____: reduce, reuse and recycle.
Reduce means “use less”. Don"t ____ things. This saves money and reduces pollution and waste going into the environment. Before we buy something new, think if it is really ____ or maybe the ____ one will be just as good! When we do buy things, choose local products if possible, and try not to buy too many things from a ____ country.
Reuse means “use again”. Use things for ____ possible. When we buy things, make sure that they ____ a long time. We should take care of them ____ they will last, and we should ____ them if we can instead of throwing them away and buying new ones. Don"t use a paper cup or a paper bag. It’s better to use a china cup and a lunch box because you can use them ____.
Recycle means “change things into something else”. Although it ____ energy to change something into something else, it’s better than ____ things or burning them. Find out ____ can be recycled in your neighbourhood and take part in recycling programmes. We should also buy ____ made from recycled materials, such as recycled paper, to help save ____.
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In the school, administrative assistants greet students at the start of the day and answer a large quantity of questions. When an assistant remembers a student’s name or even something special about that student, it communicates to him that he is cared for. The assistant can also give that extra encouragement for a student to make better choices, especially when they are visiting the principal’s office.
Meanwhile, though cafeteria workers have a short space of time to interact with students, they can make a big difference as well. Beyond meeting nutritional needs, cafeteria workers may also on occasion meet the emotional needs of the students they serve. Students benefit from positive interaction with adults, and cafeteria workers may give that extra bit of encouragement that a child needs.
Custodians (管理员) are usually underappreciated for what they offer to schools. They have to be knowledgeable about everything from cleaning to fixing the most intricate (复杂的) tools. They get to school early in the morning before teachers arrive and lock up late at night after the last student has left from the after-school event. They also make sure teachers are equipped with the necessary items and prepare the rooms so that they are ready for learning. A great custodian also gives that kind word or extra smile to that student who needs it most.
小题1:The purpose of the passage is to _______.
| A．emphasize the role teachers play in a school |
| B．highlight the contributions of other staff at school besides teachers. |
| C．tell us who make the greatest contributions to a school |
| D．explain what contributes to the success of a student |
| A．he is paid particular attention to | B．he is special |
| C．he has done something wrong | D．he has made progress in study |
| A．It’s enough for them to cook for the students. |
| B．It’s hard for them to interact with the students. |
| C．They have the most interaction with students at school. |
| D．They can also meet the emotional needs of the students. |
| A．Disappointed. | B．Dissatisfied. | C．Appreciative. | D．Doubtful. |
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