问题:共用题干 Better Solar Energy Systems:More Heat,More LightSolar photovoltaic(光电的)thermal energy systems , or PVTs , generate both heat and electricity , but _________ (51)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(晶体硅)solar cells, _______(52)lets the silicon generate more electricity but isn't a very efficient way to gather heat.That's a problem of economics.Good solar hot-water systems can harvest much more energy than asolar一electric system at a substantially lower _________(53).And it's also a space problem:photovoltaiccells can_________(54)up all the space on the roof,leaving little room for thermal applications.In a pair of studies,Joshua Pearce,an associate professor of materials science and engineering,has de- vised a_________(55)in the form of a better PVT made with a different kind of silicon.Most solar panels are made with crystalline silicon,but you can also make solar cells out of amorphous(非晶形的)silicon , commonly known________( 56 ) thin-film silicon. They don ' t create as much elec-tricity,but they are lighter,flexible,and cheaper. And,because they________(57)much less silicon,they have a greener footprint._________(58),thin-film silicon solar cells are vulnerable to some bad一news physics in the form of the Staebler-Wronski effect."That means that their efficiency drops when you_________(59)them to light一pretty much the worst possible effect for a solar cell,"Pearce explains,which is one of the__________(60)thin-film solar panels make up only a small fraction of the market.However,Pearce and his team found a_______(61)to engineer around the Staebler-Wronski effect by incorporating thin-film silicon in a new________(62)of PVT. You don't have to cool down thin-film sili- con to make it work.In fact,Pearce's group discovered that by heating it to solar-thermal operating tempera- tures,near the boiling_________(63)of water,they could make thicker cells that largely_________(64) 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_________(65)the solar cell's electrical efficiency by over 10 percent._________(53)A:rewardB:billC:costD:pay
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问题:共用题干 Europa's Watery UnderworldEuropa,one of Jupiter's 63 known moons,looks bright and icy on the surface.But appearances can be deceiving:Miles within its cracked,frigid shell,Europa probably hides giant pools of liquid water. Where scientists find liquid water,they hope to find life as well.Since we can't go diving into Europa's depths just yet,scientists instead have to investigate the moon's surface for clues to what lies beneath.In a new study,scientists investigated one group of strange ice patterns on Europa and concluded that the formations mark the top of an underground pool that holds as much water as the U.S.Great Lakes.Pictures of Europa,which is slightly smaller than Earth's moon,clearly show a tangled,icy mishmash of lines and cracks known as"chaos terrains".These chaotic places cover more than half of Europa. For more than 10 years,scientists have wondered what causes the formations.The new study suggests that they arise from the mixing of vast underground stores of liquid water with icy material near the surface.For scientists who suspect that Europa also may be hiding life beneath its icy surface,the news about the new lake is exciting."It would be great if these lakes harbored life,"Britney Schmidt,a planetary scientist who worked onthe study,told Science News."But even if they didn't,they say that Europa is doing something interesting and active right now."Schmidt,a scientist at the University of Texas at Austin,and her colleagues wanted to know how chaos terrains form.Since they couldn't rocket to Europa to see for themselves,they searched for similar forma- tions here on Earth.They studied collapsed ice shelves in Antarctica and icy caps on volcanoes in Iceland. Those features on Earth formed when liquid water mixed with ice.The scientists now suspect something similar might be happening on Europa:that as water and ice of different temperatures mingle and shift,the surface fractures.This would explain the jumbled ice sculptures."Fracturing catastrophically disrupts the ice in the same way that it causes ice shelves to collapse on Earth,"Schmidt told Science News.She and her team found that the process could be causing chaos terrains to form quickly on Europa.The new study suggests that on this moon,elements such as oxygen from the surface blend with the deep bodies of water. That mixture may create an environment that supports life.The existence of liquid water is a necessity for a life-support environment.A:RightB:WrongC:Not mentioned
问题:_____A.For example, the people in men's dreams are often other men, and the dreams often involve fighting.B.Men and women dream about different things.C.A criminal, for example, might dream about crime.D.However, one thing they agree on this: If you dream that something terrible is going to occur, you shouldn't panic.E.It was only in the twentieth century that people started to study dreams in a scientific way.F.He thought people could learn more about themselves by thinking about their dreams.
问题:共用题干 第一篇What Does GMO Free Mean?Genetically modified organisms(GMOs)in food are concern for a number of consumers who are worried about the impact that GMOs may have on their health.As a result,many companies in the late 1990s began to apply the GMO free label,indicating that their food does not contain genetically modified organisms.A number of nations legislate labeling,and in Europe,food must be labeled to indicate whether or not it contains GMOs.In the United States,however,GMO free labeling is purely voluntary and not regulated by any governmental body or organization.Since it is not regulated,there has been some question about the validity of the GMO free label in the US.A number of organizations have pressured the Food and Drug Administration(FDA),as well as the United States Department of Agriculture(USDA),to enact legislation governing food labeling in regards to GMOs.Many food activists want a label that is standardized,so that consumers who are concerned about this issue can be assured about the GMO content of products they purchase.Most US consumers have foods containing GMOs in their home.The majority of corn and soybeans grown in the US have been modified,as have several other crops.Some research indicates that many processed foods contain GMO ingredients,so for consumers who are concerned about this issue,GMO free labeling would be helpful.For consumers who want to eat natural,organic foods,knowing that the products they buy are GMO free is often very important. Although there is no federal labeling program in the US,some organic farmers and natural food producers have chosen to start their own certification programs.Getting certified through such programs can be very difficult,but many producers believe consumers will be willing to pay extra for the verification.The harmful nature of GMOs has been questioned,especially by commercial agriculture producers and seed providers.No scientific evidence has been found to suggest that genetic modification of crops is harmful to humans. Some consumers feel that it is important to be able to make conscious choices about what they eat,however,and want the ability to choose GMO free foods if they so desire.Some studies suggest that GMOs may be harmful to agriculture,with cloned genetically modified species harming overall biological diversity and modified genes finding their way into wild plants and non-modified crops.This is especially true in the case of corn,where GMO contamination became a major issue in the 1990s.Other research,however,indicates that genetically modified crops can be of benefit to the environment. Plants designed to be resistant to herbicides(除草剂)and pesticides (杀虫剂),for example,have been seen to reduce the amount of these chemicals used by farmers on both GM and non-modified crops.A number of organizations in America have pressured the Food and Drug Administration(FDA) to______.A: ban foods containing GMOsB:punish commercial agriculture producers and seed providersC:enact legislation governing food labeling in regards to GMOsD:abolish legislation governing food labeling in regards to GMOs
问题:共用题干 Wide World of RobotsEngineers who build and program robots have fascinating jobs. These researchers tinker(修补)with ma- chines in the lab and write computer software to control these devices."They're the best toys out there," says Howie Choset at Carnegie Mellon University in Pittsburgh.Choset is a roboticist,a person who designs, builds or programs robots.When Choset was a kid,he was interested in anything that moved一cars,trains,animals.He put motors on Tinkertoy cars to make them move.Later,in high school,he built mobile robots similar to small cars,Hoping to continue working on robots,he studied computer science in college.But when he got to graduate school at the California Institute of Technology in Pasadena,Choset’。labmates were working on something even cooler than remotely controlled cars:robotic snakes.Some robots can move only forward, hackward, left and right. But snakes can twist(扭曲)in many directions and travel over a lot of different types of terrain(地形)."Snakes are far more interesting than the cars,"Choset concluded.After he started working at Carnegie Mellon,Choset and his colleagues there began developing their own snake robots.Choset's team programmed robots to perform the same movements as real snakes,such as sliding and inching forward.The robot、also moved in ways that snakes usually don't,such as rolling. Choset’s snake robots could crawl(爬行)through the grass,swini in a pond and even climb a flagpole.But Choset wondered if his snakes might be useful for medicine as well.For some heart surgeries,the doctor has to open a patient's chest,cutting through the breastbone.Recovering from these surgeries can be very painful.What if the doctor could perform the operation by instead making a small hole in the body and sending in a thin robotic snake?Choset teamed up with Marco Zenati,a heart surgeon now at Harvard Medical School,to investigate theidea.Zenati practiced using the robot on a plastic model of the chest and they tested the robot in pigs. A company caikd Medrobotics in Boston is now adapting the technology for g urgerie9 on people-Even after 15 years of working with his team’s creations,"I still don't get bored of watching the motionof my robots,"Clioset says.Choset began to build robots in high school.A:RightB:WrongC:Not mentioned
问题: You will be meeting her presently.A:shortly B:currently C:lately D:probably
问题:共用题干 第三篇“Life Form Found" on Saturn ' s TitanScientists say they have discovered hints of alien life on the Saturn'5 moon.The discovery of a sort of life was announced after researchers at the US space agency,NASA,analyzed data from spacecraft Cassini, which pointed to the existence of methane-based form of life on Saturn's biggest moon.Scientists have reportedly discovered clues showing primitive alien beings are"breathing"in Titan's dense atmosphere filled with hydrogen.They argue that hydrogen gets absorbed before hitting Titan's planet-like surface covered with methane lakes and rivers.This,they say,points to the existence of some"bugs"consuming the hydrogen at the surface of the moon less than half the size of the Earth."We suggested hydrogen consumption because it's the obvious gas for life to consume on Titan,similar to the way we consume oxygen on Earth,"says NASA scientist Chris McKay."If these signs do turn out to be a sign of life,it would be doubly exciting because it would represent a second form of life independent from water-based life on Earth."To date,scientists have not yet detected this form of life anywhere,though there are liquid-water-based microorganisms on Earth that grow well on methane or produce it as a waste product. On Titan,wheretemperatures are around minus 17 Kelvin(minus 290 degrees Farenheit),a methane-based organism would have to use a substance that is liquid as its medium for living processes,but not water itself. Water is frozen solid on Titan'5 surface and much too cold to support life as we know it.Scientists had expected the Sun'5 interactions with chemicals in the atmosphere to produce a coating of acetylene on Titan'5 surface.But Cassini detected no acetylene on the surface.The absence of detectable acetylene on the Titan's surface can very well have a non-biological explana-tion,said Mark Allen,a principal investigator of the NASA Titan team."Scientific conservatism suggests that a biological explanation should be the last choice after all non- biological explanations are addressed,"Allen said."We have a lot of work to do to rule out possible non-bio- logical explanations.It is more likely that a chemical process,without biology,can explain these results."It can be inferred from Mark Allen's address that_____________.A:scientists are trying to confirm these is life on TitanB:scientists agree that a chemical process is a convincing explanationC:scientists share the opinion that a biological explanation is reasonableD:scientists are arguing over whether there is life on Titan
问题:共用题干 When Our Eyes Serve Our StomachOur senses aren't just delivering a strict view of what's going on in the world;they're af-fected by what's going on in our heads. A new study finds that hungry people see food-related words more clearly than people who'ye just eaten.Psychologists have known for decades that what's going on,inside our head affects our senses. For example,poorer children think coins are larger than they are,and hungry people think pictures of food are brighter. Remi Radel of University of Nice Sophia-Antipolis,France,wanted to investi-gate how this happens. Does it happen right away as the brain receives signals from the eyes or a lit-tle later as the brain's high-level thinking processes get involved.Radel recruited 42 students with a normal body mass index. On the day of his or her test,each student was told to arrive at the lab at noon after three or four hours of not eating. Then they were told there was a delay. Some were told to come back in 10 minutes;others were given an hour to get lunch first. So half the students were hungry when they did the ex-periment and the other half had just eaten.For the experiment,the participant looked at a computer screen. One by one,80 words flashed on the screen for about 1/300th of a second each. They flashed at so small a size thatthe students could only consciously perceive. A quarter of the words were food-related. After each word,each person was asked how bright the word was and asked to choose which of two words they'd seen一a food-related word like cake or a neutral word like boat. Each word ap-peared too briefly for the participant to really read it.Hungry people saw the food-related words as brighter and were better at identifying food-related words. Because the word appeared too quickly for them to be reliably seen,this means that the difference is in perception,not in thinking processes,Radel says.“This is something great to me. Humans can really perceive what they need or what they strive for. From the experiment,I know that our brain can really be at the disposal of our mo-tives and needs,”Radel says.There was a delay in Radel's experiment because_______.A: he needed more students to joinB: he didn't prepare enough food for the 42 studentsC: he wanted two groups of participants,hungry and non-hungryD: he didn't want to have the experiment at noon
问题:共用题干 What is the Coolest Gas in the Universe?What is the coldest air temperature ever recorded on Earth?Where was this low temperature recorded ?The coldest recorded temperature on Earth was -91℃, which_____ (51) in Antarctica(南极洲) in 1983.We encounter an interesting situation when we discuss temperatures in_________(52).Temperatures in Earth orbit(轨道)actually range from about +120℃ to -120℃. The temperature depends upon ______(53)you are in direct sunlight or in shade.Obviously,-120℃ is colder than our body can ________ (54)endure.The space temperatures just discussed affect only our area of the solar________(55).Obviously,it is hotter closer to the Sun and colder as we travel__________(56)from the Sun,Scientigtg egtimate tern- peratures at Pluto are about -210℃.How cold is the lowest estimated temperature in the entire universe?Again,it depends upon your_________(57).We are taught it is supposedly__________(58)to have atemperature below absolute zero,which is-273℃,at which atoms do not move.Two scientists,Cornell and Wieman,have successfully______(59)down a gas to a temperature barely above absolute zero. They won a Nobel Prize in Physics in 2001 for their work一not a discovery in this case.Why is the two scientists'work so important to science?In the 1920s,Satyendra Nath Bose was studying an interesting_______(60)about special light par-tidles(微粒)we now call photons(光子).Bose had trouble __________(61)other scientists to believe his theory,so he contacted Albert Einstein. Einstein’s calculations helped him theorize that atoms_______(62) behave as Bose thought一but only at very cold temperatures.Scientists have also discovered that ultra-cold(超冷)atoms can help them make the world'S atomic clocks even__________(63)accurate.These clocks are so accurate today they would oniy lose one second _________ (64)six million years!Such accuracy will help us travel in space because digtanee is velocity(速度)times time( d=vt).With the long distances involved in space _______(65),we need to know time as accurately as possibie to get accurate distance._________(53)A:whetherB:whereC:whatD:when
问题:共用题干 Learn about Light1 .Ancient civilizations were amazed by the existence of light for thousands of years. The Greek philosophers believed that light was made up of countless,tiny particles that enter the human eye and create what we call vision. However,Empedocles and a Dutch scientist named Christian Huygens believed that light was like a wave. According to them,light spread out and travelled like a straight line. This theory was accepted during the 19th century.2 .In 1905,Albert Einstein published a research paper in which he explained what is re-ferred to as the photoelectric effect. This theory explains that particles make up light.The particles Einstein was referring to are weightless bundles(束)of electromagnetic(电磁)energy called photons(光子).Today,scientists agree that light has a dual(二重)nature一it is part particle and part wave. It is a form of energy that allows us to see things around us.3 .Things that give off light are known as sources of light. During the day,the primary source of light is the sun. Other sources of light include stars,flames,flashlights,street lamps and glowing gases in glass tube.4 .When we draw the way light travels we always use straight lines. This is because nor-mally light rays travel in a straight line. However,there are some instances that can change the path and even the nature of light. They are reflection,absorption,interference(干扰), etc.5 .Physicists have attempted to measure the speed of light since the early times. In 1849, Hippolyte Fizeau conducted an experiment by directing a beam of light to a mirror located kilometers away and placed a rotating cogwheel(旋转齿轮)between the beam and the mirror. From the rate of rotation of the wheel,number of wheel's teeth and distance of the mirror,he was able to calculate that the speed of light is 313 million meters per second. In a vacuum(真空),however,the speed of light is 299,792,458 meters per second. This is about a million times faster than the speed of an airplane.Some instances such as reflection and absorption can change______.A: sources of lightB: the speed of lightC: the path of lightD: a straight lineE: a beam of lightF: a form of energy
问题: I will not tolerate that sort of behavior in my class.A: accept B: control C: observe D:regulate
问题:共用题干 第三篇Almost Human?Scientists are racing to build the world's first thinking robot.This is not science fiction: some say they will have made it by the year 2020.Carol Packer reports.Machines that walk,speak and feel are no longer science fiction.Kismet is the nameof an android(机器人)which scientists have built at the Massachusetts Institute of Technology(MIT).Kismet is different from the traditional robot because it can show human emotions.Its eyes,ears and lips move to show when it feels happy,sad or bored. Kismet is one of the first of a new generation of androids一robots that look like human beings一which can imitate human feelings.Cog,another android invented by the MIT, imitates the action of a mother. However,scientists admit that so far Cog has the mental ability of a two-year-old.The optimists(乐观主义者)say that by the year 2020 we will have created humanoids (机器人)with brains similar to those of an adult human being. These robots will be designed to look like people to make them more attractive and easier to sell to the public. What kind of jobs will they do?In the future,robots like Robonaut,a humanoid invented by NASA,will be doing dangerous jobs,like repairing space stations.They wi}{also be doing more and more of the household work for us.In Japan,scientists are designing androids that will entertain us by dancing and playing the piano.Some people worry about what the future holds:will robots become monsters(怪物)? Will people themselves become increasingly like robots?Experts predict that more and more people will be wearing micro-computers,connected to the Internet,in the future.People will have micro-chips in various parts of their body,which will connect them to a wide variety of gadgets(小装置).Perhaps we should not exaggerate(夸大)the importance of technology,but one wonders whether,in years to come,we will still be falling in love, and whether we will still feel pain.Who knows?Kismet is different from traditional robots becauseA:it thinks for itself. B:itis not like science fiction.C:it can look after two-year-olds. D:it seems to have human feelings.
问题:Michael is now merely a good friend,A:largely B:barely C:just D:rarely
问题:共用题干 Citizen ScientistsUnderstanding how nature responds to climate change will require monitoring key life cycle events-flowering,the appearance of leaves,the first frog calls of the spring-all around the world.But ecologists can't be______(51)so they are turning to non-scientists,sometimes called citizen scientists,for help.Climate scientists are not present everywhere.______(52)there are so many places in the world and not enough scientists to observe all of them,they are asking for your help in_______(53)signs of climate change across the world.The citizen scientist movement encourages______(54)people to observe a very specific research interest-birds,trees,flowers budding,etc-and send their observations______(55)a giant database to be observed by professional scientists.This helps a small number of scientists track a______(56)amount of data that they would never be able to gather on their own.______(57)like citizen journalists helping large publications cover a hyper-local beat,citizen scientists are ready for the conditions where they live.______(58)that's needed to become one is a few minutes each day or each week to gather data and_______(59)it in.A group of scientists and educators launched an organization last year______(60) the NationalPhenology(生物气候学)Network."Phenology" is what scientists call the study of the timing of events in nature.One of the group's first efforts relies on scientists and non-scientists______(61)to collect data about plant flowering and leafing every year.The program,called Project BudBurst,collects life cycle______(62)on a variety of common plants from across the United States.People participating in the project-which is______(63)to everyone-record their observations on the Project BudBurst website."People don't______(64)to be plant experts-they just have to look around and see what's in their neighborhood,"says Jennifer Scheartz,an education consultant with the project."As we collect this data,we'11 be able to make an'estimate of______(65)plants and communities of plants and animals will respond as the climate changes."_________62A:points B:wonders C:data D:interests
问题:共用题干 Germs(细菌)on BanknotesPeople in different countries use different types of money:yuan in China,pesos in Mexico,pounds in the United Kingdom,dollars in the United States,Australia and New Zeal-and. They may use different currencies,but these countries,and probably all countries,still have one thing in______(1):germs on the banknotes.Scientists have been studying the germs on money for well over 100 years. At the turn of the 20th______(2),some researchers began to suspect that germs living on money could spread disease.Most studies of germy money have looked at the germs on the currency______(3)one country. In a new study,Frank Vriesekoop and other researchers compared the germ populations found on bills of different______(4).Vriesekoop is a microbiologist at the University of Ballarat in Australia. He led the stud-y,which compared the germ populations found on money______(5)from 10 nations. The scientists studied 1,280 banknotes in total;all came from places where people buy food,like supermarkets,street vendors and cafes,______(6)those businesses often rely on cash.Overall,the Australian dollars hosted the fewest live bacteria一no more than 10 per square centimeter. Chinese yuan had the______(7)about 100 per square centimeter. Most of the germs on money probably would not cause harm.What we call“paper money”_________(8)isn't made from paper. The U. S. dollar,for ex- ample,is printed on fabric that is mostly cotton. Different countries may use different______(9)to print their money. Some of the currencies studied by Vriesekoop and his team,such as the American dollar,were made from cotton. Others were made from polymers.The three______(10)with the lowest numbers of bacteria were all printed on poly-mers. They included the Australian dollar,the New Zealand dollar and some Mexican pesos.The______(11)currencies were printed on fabric made mostly of cotton. Fewer germs lived on the polymer notes. This______(12)suggests that germs have a harder time staying alive on polymer surfaces. Scientists need to do more studies to understand______(13)germs live on, mon-ey—and whether or not we need to be concerned. Vriesekoop is now starting a study that will______(14)the amounts of time bacteria can stay alive on different types of bills.Whatever Vriesekoop finds,the fact remains:Paper money______(15)germs. We should wash our hands after touching it;After all,you never know where your money's been. Or what's living on it.2._________A: period B: year C: century D: decade
问题:共用题干 The iPad1 The iPad is a tablet computer(平板电脑)designed and developed by Apple. It is par-ticularly marketed as a platform for audio and visual media such as books,periodicals(期刊),movies,music,and games,as well as web content. At about 1 .5 pounds(680 grams), its size and weight are between those of most contemporary smartphones and laptop comput-ers.Apple released the iPad in April 2010,and sold 3 million of the devices in 80 days.2 The iPad runs the same operating system as iPod Touch and iPhone. It can run its own applications as well as ones developed for iPhone. Without modification,it will only run pro-grams approved by Apple and distributed via its online store.3 Like iPhone and iPod Touch,the iPad is controlled by a multitouch display一a break from most previous tablet computers, which uses a pressure-triggered stylus(触控笔).The iPad uses a Wi-Fi data connection to browse(浏览)the Internet, load and stream media, and install software. Some models also have a 3G wireless data connection which can connect to GSM 3G data networks. The devices is managed and synchronized(同步)by iTunes on a per-sonal computer via USB cable.4 An iPad has different features and applications one can use to execute different and in-teresting things. There are lots of iPad applications that the owner can use to enhance the way they communicate. Some of these are how to use social networking sites and other online options.One of the most common uses is for e-mail services. iPad applications like Markdown Mail allow the adoption of specific and particular options. They enable the owner to personal-ize their email accounts.5 While the iPad is mostly used by consumers it also has been taken up by business us-ers. Some companies are adopting iPads in their business offices by distributing or making available iPads to employees.Examples of uses in the workplace include lawyers responding to clients,medical professionals accessing health records during patient exams,and manag-ers approving employee requests.A survey by Frost Sullivan shows that iPad usage in work-places is linked to the goals of increased employees productivity,reduced paperwork,and in-creased revenue.Paragraph 3______A: Online StoresB: Differences from iPhoneC: Display and Data ConnectionD: Business UsageE: Features and ApplicationsF: Operating System
问题:共用题干 First Image-recognition Software1. Dartmouth researchers and their colleagues have created an artificial intelligence software that uses photos to locate documents on the Internet with far greater accuracy than ever before.2. The new system,which was tested on photos and is now being applied to videos,shows for the first time that a machine learning algorithm(运算法则)for image recognition and retrieval is ac-curate and efficient enough to improve large-scale document searches online.The system uses pix- el(像素)data in images and potentially video—rather than just text-to locate documents. It learns to recognize the pixels associated with a search phrase by studying the results from text-based image search engines. The knowledge gleaned(收集)from those results can then be ap-plied to other photos without tags or captions(图片说明),making for more accurate document search results.3 .“Over the last 30 years,”says Associate Professor Lorenzo Torresani,a co-author of the stud-“the Web has evolved from a small collection of mostly text documents to a modern,massive, fast-growing multimedia data set,where nearly every page includes multiple pictures or videos. When a person looks at a Web page, he immediately gets the gist(主旨)of it by looking at the pictures in it.Yet,surprisingly,all existing popular search engines,such as Google or Bing, strip away the information contained in the photos and use exclusively the text of Web pages to perform the document retrieval. Our study is the first to show that modern machine vision systems are accurate and efficient enough to make effective use of the information contained in image pix-els to improve document search.”The researchers designed and tested a machine vision system—a type of artificial intelligence that allows computers to learn without being explicitly programmed—that extracts semantic(语义的)information from the pixels of photos in Web pages. This information is used to enrich the description of the HTML page used by search engines for document retrieval.The researchers tested their approach using more than 600 search queries(查询)on a database of 50 million Web pa-ges.They selected the text-retrieval search engine with the best performance and modified it to make use of the additional semantic information extracted by their method from the pictures of the Web pages .They found that this produced a 30 percent improvement in precision over the original search engine purely based on text.A:using photosB: description of the HTML pageC: current popular search enginesD: document searchE: information in imagesF: machine vision systems
问题:共用题干 Ants Have Big Impact on Environment as“Ecosystem Engineers”Research by the University of Exeter has revealed that ants have a big impact on their local environment as a result of their activity as“ecosystem engineers”and predators.The study,published in the Journal of Animal Ecology,found that ants have two distinct effects on their local environment.Firstly,through moving of soil by nest building activity and by collecting food they af-fect the level of nutrients in the soil.This can indirectly impact the local populations of many animal groups,from decomposers to species much higher up the food chain.Secondly,they prey on a wide range of other animals,including larger prey which can be attacked by vast numbers of ant workers.Dirk Sanders,an author of the study from the university's Centre for Ecology and Con-servation,said:“Ants are very effective predators which thrive in huge numbers. They're al-so very territorial and very aggressive,defending their resources and territory against other predators. All of this means they have a strong influence on their surrounding area.”“In this research,we studied for the first time how big this impact is and the subtleties of it.What we found is that despite being predators,their presence can also lead to an in-crease in density and diversity of other animal groups. They genuinely play a key role in the local environment,having a big influence on the grassland food web,”Sanders said.The study,carried out in Germany,studied the impact of the presence of different com-binations and densities of black garden ants and common red ants,both species which can be found across Europe,including in the UK.It found that a low density of ants in an area in-creased the diversity and density of other animals in the local area,particularly the density of herbivores and decomposers. At higher densities ants had no or the opposite effect,showing that predation is counteracting the positive influence.Dr Frank van Veen,another author on the study,said:“What we find is that the impact of ants on soil nutrient levels has a positive effect on animal groups at low levels,but as the number of ants increases,their predatory impacts have the bigger effect一thereby counter-acting the positive influence via ecosystem engineering.”Ants are important components of ecosystems not only because they constitute a great part of the animal biomass but also because they act as ecosystem engineers.Ant biodiversity is incredibly high and these organisms are highly responsive to human impact,which obvi-ously reduces its richness. However,it is not clear how such disturbance damages the main-tenance of ant services to the ecosystem. Ants are important in below ground processes through the alteration of the physical and chemical environment and through their effects on plants,microorganisms,and other soil organisms.Dirk Sanders'study centered on how ants______.A: can manage to thrive in huge numbersB: defend their resources and territory against other predatorsC: attack those invading animals for survivalD: produce such a big impact on the environment
问题:She makes believe to be a princess.A:prevents B:pretends C:presents D:prepares
问题:共用题干 InflationBusiness and government leaders also consider the inflation rate to be an important general indicator. Inflation is a period of increased spending that causes rapid rises in prices._______(51)your money buys fewer goods so that you get_______(52)for the same amount of money as before,inflation is the problem. There is a general rise_______(53)the price of goods and services.Your money buys less.Sometimes people describe inflation as a time when"a dollar is not worth a dollar anymore".Inflation is a problem for all consumers.People who live on a fixed income are hurt the _______(54).Retired people,for instance,cannot count on an increase in income as prices rise. Elderly people who do not work face serious problems in stretching their incomes to_______(55) their needs in time of inflation.Retirement income_______(56)any fixed income usually does not rise as fast as prices.Many retired people must cut their spending to_______(57)rising prices.In many cases they must stop_______(58)some necessary items,such as food and clothing. Even _______(59)working people whose incomes are going up,inflation can be a problem. The_______(60)of living goes up,too. People who work must have even more money to keep up their standard of living. Just buying the things they need costs more.When incomes do not keep _______(61)with rising prices,the standard of living goes down.People may be earning the same amount of money,but they are not living as well because they are not able to buy as many goods and services.Government units gather information about prices in our economy and publish it as price indexes _______(62)the rate of change can be determined.A price index measures changes in prices using the price for a_______(63)year as the base.The base price is set at 100,and the other prices are reported as a_______(64)of the base price.A price index makes_______(65)possible to compare current prices of typical consumer goods,for example,with prices of the same goods in previous years._________(56)A:or B:andC:excluding D:including