时间:2016-02-22 13:59:32
第2部分 阅读判断
Lackof Oxygen Delayed the Rise of Animals on Earth
Scientistshave long speculated as to why animal species didn’t flourish sooner, oncesufficient oxygen covered the Earth’s surface. Animals began to prosper at theend of the Proterozoic period, about 800 million years ago — but what about thebillion-year stretch before that, when most researchers think there also wasplenty of oxygen?
Well,it seems the air wasn’t so great then, after all.
Ina study published Oct. 31 in Science, Yale researcher Noah Planavsky and hiscolleagues found that oxygen levels during the “boring billion” period wereonly 0.1% of what they are today. In other words, Earth’s atmosphere couldn’thave supported a diversity of creatures, no matter what genetic advancementswere poised to occur.
“There is no questionthat genetic and ecological innovation must ultimately be behind the rise ofanimals, but it is equally unavoidable that animals need a certain level ofoxygen,” said Planavsky, co-lead author of the research along with ChristopherReinhard of the Georgia Institute of Technology. “We’re providing the firstevidence that oxygen levels were low enough during this period to potentiallyprevent the rise of animals.”
Thescientists found their evidence by analyzing chromium (Cr) isotopes in ancientsediments from China, Australia, Canada, and the United States. Chromium isfound in the Earth’s continental crust, and chromium oxidation is directlylinked to the presence of free oxygen in the atmosphere.
Specifically,the team studied samples deposited in shallow, iron-rich ocean areas, near theshore. They compared their data with other samples taken from younger localesknown to have higher levels of oxygen.
Oxygen’srole in controlling the first appearance of animals has long vexed scientists.“We were missing the right approach until now,” Planavsky said. “Chromium gaveus the proxy.” Previous estimates put the oxygen level at 40% of today’sconditions during pre-animal times, leaving open the possibility that oxygenwas already plentiful enough to support animal life.
Inthe new study, the researchers acknowledged that oxygen levels were “highlydynamic” in the early atmosphere, with the potential for occasional spikes.However, they said, “It seems clear that there is a first-order difference inthe nature of Earth surface Cr cycling” before and after the rise of animals.
“If we are right, ourresults will really change how people view the origins of animals and othercomplex life, and their relationships to the co-evolving environment,” saidco-author Tim Lyons of the University of California-Riverside. “This could be agame changer.”
Fundingsources for the research included the NASA Exobiology Program and the NationalScience Foundation’s Earth-Life Transitions program, awarded to Planavsky,Reinhard, and Lyons.
Theother members of the research team included Xiangli Wang, a postdoctoral fellowat Yale; Thomas Johnson, of the University of Illinois; Danielle Thomson, ofCarleton University; Peter McGoldrick, of the University of Tasmania; andWoodward Fischer, of the California Institute of Technology.
16.The study discovered the rise of animals occurred earlier than the Proterozoicperiod.
A.Right B. Wrong C. Not mentioned
17.Many researchers believe the oxygen level was high during pre-animal times.
A. Right B. Wrong C.Not mentioned
18. The teamwas funded by several research institutes.
A.Right B. Wrong C. Not mentioned
19. Geneticadvancements triggered the rise of animals.
A.Right B. Wrong C. Not mentioned
20. Thesamples studied in the research were collected in ocean areas.
A. Right B. Wrong C.Not mentioned
21. Thestudy revealed that chromium found in Earth’s continental crust remained stablebefore and after the rise of animals.
A.Right B. Wrong C. Not mentioned
22. TimLyons liked to play computer games in his spare time.
A.Right B. Wrong C. Not mentioned
参考答案：BACBABC
第3部分 概括大意与完成句子
FirstImage-recognition Software
1.Dartmouth researchers and their colleagues have created an artificial 1 ,software that uses photos to locate documents on the Internet with far gre jthan ever before.
2.The new system, which was tested on photos and is now being applied to , Ishows for the first time that a machine learning algorithm (运算法则)or ,ma9e I recognition and retrieva l is accurate and efficient enough toimprove large seaie , document searches online. The system uses pixel (像素)data in images and potentia y video — rather than just text — to locatedocuments. It learns to recognize the pixels associated with a search phrase bystudying the results from text-based image search engines. The knowledgegleaned (收集) from those results can then beapplied to other photos without tags or captions making for more accuratedocument search results.
3."Over the last 30 years," says Associate Professor Lorenzo Torresani,a co-author of the study, "the Web has evolved from a small collection ofmostly text documents to a modern, massive, fast-growing multimedia dataset,where nearly every page includes multiple pictures or videos. When a personlooks at a Web page, he immediately gets the gist (主旨)of it by looking at the pictures in it. Yet, surprisingly, all existing popularsearch engines, such as Google or Bing, strip away the information contained inthe photos and use exclusively the text of Web pages to perform the documentretrieva l. Our study is the first to show that modern machine vision systemsare accurate and efficient enough to make effective use of the informationcontained in image pixels to improve document search."
4.The researchers designed and tested a machine vision system — a type ofartificial intelligence that allows computers to learn without being explicitlyprogrammed — that extracts semantic (语义的) information from thepixels of photos in Web pages. This information is used to enrich thedescription of the HTML page used by search engines for document retrieva l. Theresearchers tested their approach using more than 600 search queries (查询)on a database of 50 million Web pages. They selected the text-retheva l searchengine with the best performance and modified it to make use of the additionalsemantic information extracted by their method from the pictures of the Webpages. They found that this produced a 30 percent improvement in precision overthe original search engine purely based on text.
23. Paragraph 1 __B__
24. Paragraph 2 __C__
25. Paragraph 3 __E__
26. Paragraph 4 __D__
A.Popularity of the new system
B.Publication of the new discovery
C.Function of the new system
D.Artificial intelligence software created
E.Problems of the existing search engines
F.Improvement in document retrieva l
27. The new system does documentretrieva l by __C__.
28. The new system is expected toimprove precision in __B__.
29. When performing documentretrieva l the existing search engines ignore __A__
30. The new system was found moreeffective in document search than the __E__
A.information in images
B.current popular search engines
C.using photos
D.machine vision systems
E.document search
F.description of the HTML page
第4部分 阅读理解
Better Solar Energy Systems: More Heat,More Light
Solar photovoltaic thermal energy systems,or PVTs, generate both heat and electricity, but until now they haven’t been very good at the heat-generating part compared to a stand-alone solar thermal collector. That’s because they operate at low temperatures to cool crystalline silicon solar cells, which lets the silicon generate more electricity but isn’ta very efficient way to gather heat.
That’s a problem of economics. Good solar hot-water systems can harvest much more energy than a solar-electric system at a substantially lower cost. And it’s also a space problem: photovoltaic cells can take up all the space on the roof, leaving little room for thermal applications.
In a pair of studies, Joshua Pearce, anassociate professor of materials science and engineering, has devised a solution in the form of a better PVT made with a different kind of silicon. His research collaborators are Kunal Girotra from Thin Silicon in California and Michael Pathak and Stephen Harrison from Queen’s University, Canada.
Most solar panels are made with crystalline silicon, but you can also make solar cells out of amorphous silicon, commonly known as thin-film silicon. They don’t create as much electricity, but they are lighter, flexible, and cheaper. And, because they require much less silicon,they have a greener footprint. Unfortunately, thin-film silicon solar cells are vulnerable to some bad-news physics in the form of the Staebler-Wronski effect.
“That means that their efficiency drops when you expose them to light— pretty much the worst possible effect for a solar cell,” Pearce explains,which is one of the reasons thin-film solar panels make up only a small fraction of the market.
However, Pearce and his team found a way to engineer around the Staebler-Wronski effect by incorporating thin-film siliconin a new type of PVT. You don’t have to cool down thin-film silicon to make it work. In fact, Pearce’s group discovered that by heating it to solar-thermal operating temperatures, near the boiling point of water, they could make thicker cells that largely overcame the Staebler-Wronski effect. When they applied the thin-film silicon directly to a solar thermal energy collector,they also found that by baking the cell once a day, they boosted the solar cell’s electrical efficiency by over 10 percent.
31. PVTs are not efficient in
A. creating electricity.
B. cooling silicon solar cells.
C. generating heat.
D. powering solar thermal collectors.
32. One of the problems PVTs have is that
A. their thermala pplications are costly.
B. they are too expensive to afford.
C. it is hard to fix them on the roof.
D. they occupy too much space.
33. Which of the following is NOT mentioned as an advantage of thin-film silicon solar cells?
A. They are flexible.
B. They are less expensive.
C. They are electrically efficient.
D. They are environment friendly.
34. Thin-film solar panels do not sell well on market because
A. they do not work well if exposed to light.
B. their advantages are not well-recognized.
C. they need improving in appearance.
D. they are not advertised.
35 Which of the following statements is true?
A. New techniques have been developed to produce thin-film silicon.
B Thin-film silicon works efficiently at low temperature.
C Thin-film silicon's electrical efficiency improves when heated up.
D Anew material enlarging the Staebler-WronsKi effect has been created.
译文：
第十三篇 更有效的太阳能系统：更多热量，更强灯光
太阳能光伏热能系统，也叫PVT，能够生成热量和电能。与太阳热能单机收集器相比，传统太阳能光伏热能系统在转换热能方面效率不是很高。原因是，为了使晶体硅太阳能电池冷却，该系统在低温下工作。因此，硅体能产出更多的电能，却不能有效地产生热量。
第一，经济问题。好的太阳能热水系统比太阳能电力系统收集的能量更多，而且成本低得多。第二，空间问题。光电管占去屋顶的所有的空间，几乎没有空间留给热能的产出。
在一项研究中，材料科学与工程副教授Joshua Pearce找到了一个解决方案：用另外一种硅制成PVT来解决效能问题。他的合作者有：来自加利福尼亚ThinSilicon的Kunal Girotra和加拿大皇后大学的Michael Pathak和Stephen Harrison。
大部分太阳能电池板是由晶体硅制成，但是，你也可以用非晶硅制成太阳能电池，这种非晶体硅通常被叫作薄膜硅。它们不能产生那么多的电能，但是更亮、更灵巧、成本更低。而且，由于它们需要的硅较少，它们更环保。不幸的是，薄膜硅太阳能电池易受SWE效应攻击(在光的照射下，非晶硅氢的导电性短时间内显著衰退，这种特性被称为SWE效应)。
“当被暴露在光线下，那就意味着它们的能效会降低——这几乎是太阳能电池最可能糟糕的效应。”Pearce解释道。这就是薄型太阳能板只占有一少部分市场的原因。
然而，Pearce和他的团队把薄膜硅合成为一种新型的PVT，可以克服或绕过SWE效应。这种方法可以不用冷却薄膜硅而让它们产生效能。事实上，Pearce团队发现，通过把薄膜硅加热到太阳热能操作温度，即临近水的沸点，可以把它制成较厚的电池，从而可以遏制SWE效应。当把薄膜硅直接应用到太阳热能集热器时，他们也发现，如果一天把太阳能电池加热一次，那么太阳能的电力效能会增加10%。
第二篇
Face Masks May Not Protect from Super-Flu
If a super-flu strikes, face masks may not protect you. Whether widespread use of masks will help, or harm,during the next worldwide flu outbreak is a question that researchers are studying furiously. No results have come from their mask research yet.
However, the government says people should consider wearing them certain stations anyway, just in case.
But it's a question the public keeps asking while the government is makingpreparations for the next flu pandemic (大流行).So the Centers for Disease Control and Prevention (CDC) came up with preliminary guidelines. "We don’t want People wearing them everywhere," said the CDC. The overall recommendation really is to avoid exposure.”
When that is not possible, the guidelines say you should consider wearing a simple surgical mask if you are in one of the three following situations. First, you’re healthy and can’t avoid going to a crowded place. Second, you're sick and think you may have close contact with the healthy, such as a family member checking on you. Third, you live with someone who's sick and thus might be in the early stages of infection, but still need to go out.
Influenza pandemics can strike when the easy-to-mutate (变异)flu virus shifts to a strain(菌株)that people never have experienced. Scientists cannot predict when the next pandemic will arrive, although concern is rising that the Asian bird flu might trigger one if it starts spreading easily from person to person.
During the flu pandemic, you should protect yourself. Avoid crowds, and avoid close contact with the sick unless you must care for someone. Why aren’t masks added to this self-protection list? Because they can help trap virus-laden droplets flying through the air with a cough or sneeze. Simple surgical masks only filter the larger droplets (飞沫). Besides, the CDC is afraid masks may create a false sense of security. Perhaps someone who should have stayed home would don(戴)an ill-fitting mask and hop on the subway instead.
Nor does flu only spread through the air. Say someone covers a sneeze with his or her hand, then touches a doorknob or subway pole. If you touch that spot next and then put germy hands on your nose or mouth, you’ve been exposed. It’s harder to rub your nose while wearing a mask, so your face may get pretty sweaty under masks. You reach under to wipe that sweat, and may transfer germs caught on the outside of the mask straight to the nose. These are the problems face masks may create for their users.
Whether people should or should not use face masks still remains a question. The general public has to wait patiently for the results of the mask research scientists are still doing.
36 .题干】What is the passage mainly about?
选项】
A.Widespread use of face masks.
B.Possibility of a worldwide flu outbreak
C.New discoveries of a face mask research.
D.Effectiveness of wearing face masks
37.题干】The CDC suggests that people
选项】
A.stay alone when being sick.
B.wear face masks when going to a crowded place.
C.wear face masks wherever possible.
D.remain at home if living with someone who’s sick.
38. 题干】The word "that" in Paragraph 3 refers to
选项】
A.making preparations.
B.avoiding exposure
C.coming up with guidelines.
D.wearing face masks everywhere.
39. 题干】Which of the following statements is true?
选项】
A.Scientists warn the next flu is coming soon.
B.Asian bird flu is spreading easily from person to person.
C.Masks protect people because they keep viruses away.
D.Masks are not effective if a flu strikes.
40. 题干】One of the concerns the CDC has is that
选项】
A.masks may give people a wrong assumption of being safe.
B.the sick may not wear masks and go out.
C.fluvims may spread via public transportation.
D.healthy people may not know how to protect themselves.
第5部分 补全短文
Gorillas have a word for it
Kokois the first gorilla to have been taught sign language (a way of communicatingby using hands and fingers rather than speech). With a vocabulary of more than1000 words, she is the first to prove we share a world with other intelligentbeings who feel emotions, look forward to celebrations and also have a sense ofhumour.
The30-year study of Koko has redefined science's concept of gorilla intelligence.According to some scientists, genetically there is only a 2% difference betweengorillas and humans: we share the same blood type, have the same number ofhairs per square inch and also the same temperament. But what had not beenrecognised by the scientific community was that gorillas have the ability tolearn a language and have complex emotions.
Kokolives in the Santa Cruz mountains in North America, in a wooded spotoverlooking a valley. She has her own home, with curtains, and a nest ofblankets, which is her bed, in one corner. She has a barrel on which she likesto sit when 'talking' to humans - gorillas feel more secure when they can lookdown on others - while her toys are spread everywhere. In addition she has anoutside enclosure where she spends her days when it is not raining.
Itis her conversations with her teacher, Dr Penny Patterson, that are inspiring.Penny explains: ‘The reality of my discovery is that our abilities as humans,our skills, sensibilities and emotions are very similar to the great apes. Whatwe have learnt is that gorillas are more complex than we ever imagined.'
Whenshe began teaching Koko sign language, placing the little fingers of theone-year-old gorilla into the correct positions for 'drink', 'eat', 'more', andrewarding her with food, Dr Patterson had no idea how quickly Koko would learn.“At first, it seemed Koko was using sign language as a tool to get something,”says Patterson. 'It became the kind of reward system that you could expect of acat or a dog. But early in her training, she began to combine signs that mademe think she was capable of more.’ Now Koko is so proficient in sign languagethat if she doesn't know a word she invents one. For example, she didn't knowthe word for 'ring', so she combined the signs for ‘finger’ and 'bracelet' toexpress it.
DrPatterson continues: ‘Koko loves babies and young people. And when she is askedwhat gorillas like best, she always says "Gorilla love eat, good’’.' Oneof Patterson's favourite stories demonstrates Koko's sense of humour. When avisitor asked her to show him something scary, she held up a mirror to his face!
WhenPatterson asked her what she would like for her 11th birthday, Koko signed thatshe wanted a cat. The story of Koko’s cat enabled Patterson to learn more abouther student: the cat was hit by a car and Patterson had to break the news toKoko, who signed 'cry, sad, frown'. Then, once alone, Patterson heard Koko makethe gorilla's distress call: a loud series of hoots.
Fromthe age of three, Koko shared her accommodation with Michael who was intendedas a mate. However,
Michaeldied suddenly two years ago of a heart attack. ‘Koko went into a depressionfollowing Michael's death,’ says Patterson. ‘She would sit for hours with herhead hung low looking upset.'
DrPatterson asked her if she was looking forward to moving to Hawaii, wherePatterson is raising money to build a gorilla refuge. Koko signed ‘Yes',provided she could have curtains in her new home!
第6部分 完形填空
Robotic Highway Cones
A University of Nebraska professor has developed robotic cones and barrels. These robotic cones and barrels can move out of the way, or into place, from computer commands made miles away. They can even be programmed to move on their own1 at any particular part of the day, said Shane Fanitor, an assistant professor of mechanical engineering at Nebraska.
For example, if workers arrived at 6 am, the cones could move from the side of the highway to block off the lane at that time. And they can return to the original place at the end of the day. “It just seems likea very good application for robots,” Farritor said. “The robotic cones would also help remove people from hazardous jobs on the highway putting barrels and cones into place,” Fanitor said in a report oh his creation.
Work on the idea began in 2002 using a National Academy of Sciences grant. The fund allowed Farritor to work on the project with graduate students2 at Nebraska and his assistant Steve Goddard.
The robots are placed at the bottomof the cones and barrels and are small enough not to greatly change the appearance of the construction aides. “It would look exactly the same,”Farritor said. “Normally there’s a kind of rubbery, black base to them. Were place that with a robot.
Farritor has talked with officials from the Nebraska Department of Roads about how the robots would be most useful to what they3 might need.
The robots could come in handy4 following a slow-moving maintenance operation, like painting a stripe on a road or moving asphalt, where now the barrels have to be picked up and moved as the operation proceeds. “That way you don’t have to block off a 10-mile strip forthe operation,5” Fanitor said.
While6 prototypes have been made, they are not in use anywhere. Farritor said he has applied for apatent and is considering what to do next. Heis thinking about starting a small business. He is also thinking about marketing the robots to roads departments and others across the country who7 may benefit from them.
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