题目
题型:不详难度:来源:
When a bird flaps(振翅) its wings, it stirs the air around it and causes it to move indifferent directions. Scientist found in the study that the air creates an upward-moving wave at the tips of the wings, which means that if a bird flies around the wingtips of another bird, it can get a boost(抬高) from the rising air and therefore use less energy to stay in the air.
Apart form the "free ride" strategy, scientists were also surprised to observe that migrating birds timed their wing beats and adjusted their positions in a very precise way to maximize the lifting effect while avoiding areas where the air move downward.
"They"re able to sense what"s going on from the bird in front, where this "good air" is coming from and now how to position themselves perfectly in it," lead researcher Steven Portugal told BBC.
In fact, the "V" formation has long thought to help birds fly more efficiently(效率搞地). A previous study showed that birds" heart rates went down when they were flying together in a "V" formation. Jet fighters were also found to be able reduce their energy use by up to 18% by staying near the wingtips of other jet fighters. Both of these findings led scientists to suspect that the "V" formation had an efficiency purpose, but until now they still lack proof.
"For scientists, the new study provides an insight into an interesting natural phenomenon. But it could mean even more for aircraft companies — helping them understand how they can imitate that with their plane formations to save fuel, said Portugal."
小题1:What is the author"s purpose in writing this article?
A.To explain how birds benefit from migration. |
B.To introduce how migrating birds find their way. |
C.To tell some applications of migrating birds" "V" formations. |
D.To report new findings about migrating birds" "V" formations. |
A.they don"t change their lead birds during the whole journey |
B.they fly in "V" formations to protect themselves against enemies |
C.they form the shape of a "V" to make best use of the lifting effect |
D.the air they stir around makes it hard for the birds behind to fly fast |
A.It might inspire aircraft companies to think of ways to improve efficiency. |
B.It has proved that the "V" formation can improve in efficiency in many fields, |
C.It has led scientists to discover that birds" heart rates go down when they fly in a "V". |
D.It shows that the best formation of jet fighters in battle should be a "V" formation. |
A.use | B.copy | C.change | D.learn |
答案
小题1:D
小题2:C
小题3:A
小题4:B
解析
小题1: D
【试题解析】推理题。根据文章主题段第一段最后一句Now, a research group from University of London may have found the answer ― migrating birds fly in a "V" to save energy, according to a study published in the journal Nature.可知本文是对候鸟使用V字形飞行的原因的研究的新的发现。故D正确。
小题2: C
【试题解析】推理题。根据文章第三段Apart form the "free ride" strategy, scientists were also surprised to observe that migrating birds timed their wing beats and adjusted their positions in a very precise way to maximize the lifting effect while avoiding areas where the air move downward.可知候鸟按照V字形飞行是为了更好地利用鸟儿拍打翅膀带来的lifting的影响,让飞行的效率更高。故C正确。
小题3: A
【试题解析】推理题。根据文章最后2行. But it could mean even more for aircraft companies — helping them understand how they can imitate that with their plane formations to save fuel, said Portugal."可知飞机制造商可以利用这一研究结果来提高飞机飞行的效率。故A正确。
小题4: B
【试题解析】猜测词义题。根据本句But it could mean even more for aircraft companies — helping them understand how they can imitate that with their plane formations to save fuel, said Portugal."可知这一新发现能够帮助那些飞机制造商,更好地理解他们如何模仿鸟儿的这一飞行特点来改造飞机以节省燃料。该该词是指“模仿”,故B正确。
【长难句解析】
Scientists have been puzzled by the phenomenon that migrating birds fly not just in groups all the time, but in "V" formations and they have tried to figure out what benefit birds get from this particular formation.
【翻译】科学家对于这一现象感觉很困惑,候鸟飞行的时候不仅仅是一直都是一群鸟儿一起飞而且是按照V字形在飞行。他们一直都想知道从这种特殊的飞行模式中鸟儿能够得到什么样的好处。
【分析】本句中有一个同位语从句that migrating birds fly not just in groups all the time, but in "V" formations,对前面的名词the phenomenon进行解释说明,that在这个同位语从句中不充当任何成分,只是一个引导词而已。同时动词figure后面还有一个由what引导的宾语从句,what在宾语从句中做主语。
核心考点
试题【Scientists have been puzzled by the phenomenon that migrating birds fly not just】;主要考察你对题材分类等知识点的理解。[详细]
举一反三
Controlled burns are often employed by government authorities to reduce fuel buildup,and clean up the fallen leaves,and thus,prevent the spread of forest fires to a vast area.Regular controlled burns can also help maintain biodiversity(生物多样性),as the smoke and heat produced in the process can facilitate(促进)the growth of seeds of certain plant species.Apart from these,responsible human behavior can help reduce the number of forest fires to a great extent.In fact,we can reduce the number of wildfires dramatically by not leaving behind any source of fire in the forest.
Forest fires can affect climate and weather to a great extent,besides causing severe damage to valuable trees.Wildfires can increase the level of greenhouse gases(water vapor, carbon dioxide,etc),and therefore increase pollution and global warming.However, they are also an important part of the ecosystem,and many plants depend on the heat and smoke generated by wildfires for their growth and reproduction.But large wildfires can cause extensive damage to the ecosystem,which again highlights the importance of effective control and prevention of forest fires·
小题1:What may be the best title for this passage?
A.Control and Prevention of Forest Fires |
B.How to Keep Ecological Balance |
C.Effects of Forest Fires |
D.Methods of Fire Spread Control |
A.keep close monitoring of forest fires |
B.prevent the forest fire from occurring |
C.protect the animals there |
D.stop the wildfire from spreading |
A.burn the rubbish and keep the forest clean |
B.help keep ecological balance of nature |
C.reduce fuel buildup and limit forest fires spread |
D.provide reasonable conditions for some plants’growth |
A.a new forest will appear soon |
B.it promotes the development of some seeds |
C.nature keeps its balance only by wildfires |
D.it makes the trees grow faster than before |
A.the greenhouse gases are caused mainly by wildfires |
B.wildfires have both positive and negative effects |
C.people should be aware of the necessity of wildfires |
D.all the valuable trees disappear owing to wildfires |
According to the US Food and Drug Administration, nearly 90 percent of people worldwide consume about 200 milligrams of caffeine each day. That" s equivalent to about one strong cup of coffee a day. Writing in " Nature Neuroscience" , Johns Hopkins University researchers say their findings show that caffeine strengthens certain memories for up t0 24 hours after being taken in.
" We"ve always known that caffeine has cognitive-enhancing effects (促智效果) , but its ,particular effects on strengthening memories and making them resistant to forgetting has never been examined in detail in humans, " said senior author of the paper Michael Yassa. " We re- port for the first time a specific effect of caffeine on reducing forgetting over 24 hours. " Conducting a double-blind trial, the researchers worked with a test group of people who didn"t regularly consume caffeinated products. Five minutes after studying a series of images, the test subjects were given either a placebo(无效对照剂) or a 200-milligram caffeine tablet.
To check the caffeine levels of their test subjects, the research team took saliva samples (唾液样品) from them before they took their tablets and again one, three and 24 hours after- wards.
Both groups of test participants ( those who took the placebo and those who took the caffeine tablet) were tested the following day to see if they could recognize the images they" d seen the previous day.
The test included showing the test subjects another series of images that included some new images , those that were shown the previous day, as well as other images that were similar, but not the same as those they had viewed earlier.
The researchers found that more members of the group who were given the caffeine tablets were able to correctly identify some of the new images as " similar" to previously viewed images rather than incorrectly identifying them as the same.
"We also know that caffeine is associated with health and longevity(长寿) and may havesome protective effects from cognitive decline like Alzheimer" s disease (阿尔茨海默症). " said Yassa.
小题1:The purpose of the new research is
A.to survey how much caffeine people consume a day |
B.to write the paper " Nature Neuroscience" |
C.to prove caffeine has cognitive-enhancing effects |
D.to examine caffeine " s memory-strengthening effects in detail |
A.giving the test subjects placebos or caffeine tablets |
B.checking the caffeine levels of the test subjects |
C.encouraging the test subjects to drink more coffee |
D.showing the test subjects series of images |
A.By recognizing images they " d seen the previous day. |
B.By taking the caffeine tablets instead of placebos. |
C.By identifying the new images as the same. |
D.By telling the differences between new images. |
A.Ways to achieve health and longevity. |
B.The effects caffeine has on health. |
C.The treatment for Alzheimer" s disease. |
D.The harmful effects of cognitive decline. |
Most of the technology is available now, but convincing more people that they don"t need to read a newspaper is the next step. But resistance to computer newspapers may be stronger from within journalism. Since it is such a cultural change, it may be that the present generation of journalists and publishers will have to die off before the next generation realizes that the newspaper industry is no longer a newspaper industry. Technology is making the end of " traditional newspapers unavoidable.
Despite technological advances, it could take decades to replace newsprint with computer screens. It might take 30 t0 40 years to complete the changeover because people need to buy computers and because newspapers have established financial interests in the paper industry.
小题1: Which of the following is NOT an advantage of computer newspapers?
A.They are cheaper than traditional newspapers. |
B.They are more convenient to read. |
C.You can choose the kind of voice you want to hear. |
D.You can easily save information for future use. |
A.The technology is impossible now. |
B. Computer newspaper s are too expensive. |
C.The popularization of computers needs a long time. |
D.Traditional newspapers are easier to read. |
A.they don"t know how to use computers |
B.they think computer newspapers take too much time to read |
C.they think the new technology is bad |
D.they have been trained to write For traditional newspapers |
A.all technological changes are good |
B.new technologies don"t always replace old ones |
C.new technologies will eventually replace old ones |
D.traditional newspapers are here to stay for another century |
A.Computer newspapers are well liked. |
B.Newspapers of the future will be on the computer. |
C.Newspapers are out of fashion. |
D.New communications technology. |
Groundhog Day(土拔鼠节),falls on the 2nd of February every year.It is observed in the United States and Canada.While this day may be a public holiday and a bank holiday,it is not a compulsory holiday declared by the government.But this is not so for all the states.State-wise holidays may vary.
Ever heard of Punxsutawney Phil? Groundhog Day is observed because of this groundhog.The day is indeed about a groundhog.Punxsutawney is the name of an apparently weather forecasting groundhog.He lives in his burrow(洞穴)on Gobler’s Knob,Punxsutawney in Pennsylvania,for a short period before the 2nd of February every year.On the 2nd of February,Phil comes out from his burrow and looks for his shadow.If he sees his shadow and goes back into the burrow,then America will have an extended winter of six weeks,But if he cannot see his shadow,and he remains outside.It means winter will soon end and spring will arrive very shortly .Phil has been‘predicting’the length of winter in this manner for almost a century and they have always been almost 100% accurate.
Groundhog Day is celebrated in some parts of the USA and Canada.The largest celebration is held at Punxsutawney,Pennsylvania.People come in scores to visit Punxsutawney Phil.They wait eagerly, camping days in advance,to see the small groundhog appear from his burrow,check for his shadow and either go back in or stay out.People cheer when they hear it is time for winter to end and celebrate by eating sweets and singing and dancing.Today.the Groundhog Day is a widespread tradition and an exciting event.
小题1:People celebrate Groundhog Day because ______________.
A.some sweets are provided on Groundhog Day |
B.more and more people love groundhogs |
C.the groundhog predicts the beginning of spring |
D.Punxsutawney Phil is worth respecting |
A.Human civilization has a long history. |
B.Some old traditions should be carried on. |
C.Human civilization develops very fast. |
D.Some old traditions have disappeared. |
A.forecasts the weather based on his shadow |
B.witnesses the history of human development |
C.organizes celebrations on Groundhog Day |
D.gives performances on Groundhog Day |
A.groundhogs will replace TV weathermen soon |
B.groundhogs can forecast the weather accurately |
C.Groundhog Day is becoming popular in the US and Canada |
D.a longer shadow of a groundhog indicates a longer winter |
A.Winter will end if the groundhog goes back into the burrow. |
B.Groundhog Day is a compulsory’holiday in the US and Canada. |
C.A groundhog will remain outside if he sees his shadows on 2nd,Feb. |
D.The celebration in Punxsutawney attracts large numbers of visitors. |
* Plan practically. Contact the organization a few months before leaving and find out if there are materials which are rare and hard to attain for the project. What you often consider plentiful here, such as nails or hammers, is in great need in other parts of the world.
* Do the project together, not on your own. You are a guest in the community. The most successful result is not that you build something and walk away, but that you and the community build something as a team. Share skills and build together.
* Be flexible. Not everything is going to happen as planned. Often the other country doesn"t have the right tools, manpower, transportation or funds to get all the needed work done. In a word, they lack infrastructure(基础设施).
* Contact with the people in the community. Often you will have "downtime" outside of the range of the project. Rather than retreat to the group with whom you traveled, be sure to spend time with the people of the community. Listen to the things about their lives. If you can"t speak the language, smiles work wonders. And you will be surprised ― you will find a way to community.
Volunteering is a special and life-long experience for everyone involved. Be prepared that the person who may be changed most is you. It"s a joyful, often careful experience which will encourage you to view yourself, your neighbors and your world quite differently.
小题1: When you volunteer to join in a project, you are advised to .
A.build something and walk away |
B.make good preparation in advance |
C.avoid involving locals in activities |
D.depend on yourself to solve problems |
A.reduce challenge in the world |
B.determine the future of a volunteer |
C.change a person"s opinion of the world |
D.benefit volunteers most in their learning |
A.What prepares you to become a volunteer. |
B.Where volunteers are needed most in the world. |
C.Why volunteering is popular with young people. |
D.How volunteers develop a relationship with local people. |
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