单选题The reference to the peppered moth in line 43 is used to ______.Aprovide an example of a species that has been shown to undergo macroevolutionBdemonstrate that many species have undergone the process of microevolutionCprove that all living things descended from a common ancestorDquestion the use of the fossil record to support DarwinismEhighlight the dangers to the environment of pollution from industrial complexes
单选题
The reference to the peppered moth in line 43 is used to ______.
A
provide an example of a species that has been shown to undergo macroevolution
B
demonstrate that many species have undergone the process of microevolution
C
prove that all living things descended from a common ancestor
D
question the use of the fossil record to support Darwinism
E
highlight the dangers to the environment of pollution from industrial complexes
参考解析
解析：
作者用白桦尺蛾来证明许多物种都经历了微进化这个过程。故选A项。
作者用白桦尺蛾来证明许多物种都经历了微进化这个过程。故选A项。
相关考题：
"Hidden" Species May Be Surprisingly CommonCryptic species animals that appear identical but are genetically quite distant—may be much more widespread than previously thought. The findings could have major implications in areas ranging from biodiversity estimates and wildlife management, to our understanding of infectious diseases and evolution.Reports of cryptic species have increased dramatically over the past two decades with the advent of relatively inexpensive DNA sequencing technology. Markus Pfenninger and Klaus Schwenk, of the Goethe-Universitat, in Frankfurt, Germany, analyzed all known data on cryptic animal species and discovered that they are found in equal proportions throughout all major branches of the animal kingdom and occur in equal numbers in all biogeographieal regions.Scientists had previously speculated that cryptic species were predominantly found in insects and reptiles, and were more likely to occur in tropical rather than temperate regions. "Species that are seemingly widespread and abundant could in reality be many different cryptic species that have low populations and are highly endangered. " Says Pfenninger. Until the genetic information of all species in at least one taxon is thoroughly studied, no one will know just how many cryptic species exist. "It could be as high as 30%. " Pfenninger says."I'm extremely surprised by their results. " Says Alex Smith of the University of Guelph in Ontario, Canada. "It's a call to arms to keep doing the broad kind of genetic studies that we are doing. "Sampling as many individuals as possible, scientists hope to complete work on all fish and birds in another 5 to 10 years. Once either of these taxonomic groups is completed, Pfenninger says researchers will be able to decide how many cryptic species exist throughout the animal kingdom.Examples of cryptic species include the African elephant. A 2001 study found the elephants were actually two genetically distinct, non-interbreeding species, the African bush elephant and the African elephant. The species are currently listed as vulnerable and threatened, respectively, by the World Conservation Union (WCU).The reclassifications are more than an academic exercise. They define populations that have evolved independently of each other and whose genetic differences can have significant consequences. In the early 1900s misidentification of mosquito species based on morphology confused attempts to control malaria in Europe. Ultimately, what was thought to be a single species was actually made up of six sibling species, only three of which transmitted the disease. "The basic unit in biology is always the species, and you have to know what you are dealing with. " Pfenninger says. Much previous research is now no longer used, he says, because it is not clear what species was being studied.Which of the following about the significance of the research on cryptic species is NOT true?A．The results of the research can help the development of many other research areas.B．The results of the research can help the development of biodiversity estimates.C．The results of the research can help our understanding of infectious disease evolution.D．The results of the research can help our understanding of "survival of the fittest. "
We can infer from the passage that_____.［A］ Shearer has experienced many violent incidents ［B］ new tools have been used to investigate terrorists［C］ FBI has been active in the war on eco-terrorism ［D］ ELF openly declares its beliefs and ends
共用题干Ants as a Barometer of Ecological ChangeAt picnics,ants are pests.But they have their uses.In industries such as mining,farming and forestry,they can help gauge the health of the environment by just crawling around and being antsy.It has been recognized for decades that ant—which are highly sensitive to ecological change—can provide a near-perfect barometer of the state of an ecosystem.Only certain species, for instance,will continue to thrive at a forest site that has been cleared of trees._______(46) And still others will move in and take up residence.By looking at which species populate a deforested area,scientists can determine how “stressed”the land is._______(47)Ants are used simply because they are so common and comprise so many species.Where mine sites are being restored,for example,some ant species will recolonize the stripped land more quickly than others._______(48)Australian mining company Capricorn Coal Management has been successfully using ant surveys for years to determine the rate of recov-ery of land that it is replanting near its German Creek mine in Queensland.Ant surveys also have been used with mine-site recovery projects in Africa and Brazil,where warm climates encourage dense and diverse ant populations.“We found it worked extremely well there,”says Jonathan Majer,a professor of environmental biology.Yet the surveys are perfectly suited to climates throughout Asia,he says,because ants are so common throughout the region. As Majer puts it:“That's the great thing about ants.”Ant surveys are so highly-regarded as ecological indicators that governments worldwide accept their results when assessing the environmental impact of mining and tree harvesting._______ (49)Why not?Because many companies can't afford the expense or the laboratory time needed to sift results for a comprehensive survey.The cost stems,also,from the scarcity of ant specialists. ______(50)_______(46)A: This allowed scientists to gauge the pace and progress of the ecological recovery.B: Yet in other businesses,such as farming and property development,ant surveys aren't used widely.C: Employing those people are expensive.D: They do this by sorting the ants,counting their numbers and comparing the results with those of earlier surveys.E: The evolution of ant species may have a strong impact on our ecosystem.F: Others will die out for lack of food.
共用题干第二篇The Book of LifeSo far,scientists have named about 1.8 million living species,and that's just a fraction of what proba- bly exists on Earth.With so many plants,animals,and other creatures covering the planet,it can be toughto figure out what type of spider is moving up your leg or what kind of bird is flying by.A soon-to-be-launched Web site might help. An international team of researchers has announced thecreation of a Web-based Encyclopedia of Life(EoL).The project aims to catalog every species on Earth in asingle,easy-to-use reference guide.To get the encyclopedia started,the creators will use information from scientific databases that alreadyexist.And eventually,in special sections of the site,nonscientists with specialized knowledge will get to join in.Bird-watchers,for example,will be able to input which birds they've seen and where.The technologyfor this kind of tool has only recently become available.As the EoL develops, you might find it useful for school projects.The site will feature special pages forkids who are studying ecosystems（生态系统）in their neighborhoods. To make sure the encyclopedia isaccurate,scientists will review much of the information added to it. People who visit the site will be able tochoose to leave out pages that haven't been reviewed.Another convenient feature of the EoL is that you'll be able to pick the level of detail you see to matchyour interests,age,and current knowledge.If you wanted to learn about bears for a science class report,forexample,you could use the"novice"setting to get basic information about the animals.On the"expert" setting,on the other hand,you could get much more detailed information about the history,literature and exploration of bears.It now takes years for scientists to collect all the data they need to describe and analyze species.Thecreators of the Encyclopedia of Life hope that their new tool will speed that process."Spider" and"bird"mentioned in Paragraph 1 are examples to illustrate_______________.A:animals are people's friendsB:there are numerous living species on EarthC:it is easy to see spiders and birdsD:there are many types of spiders and birds
共用题干第二篇The Book of LifeSo far,scientists have named about 1.8 million living species,and that's just a fraction of what proba- bly exists on Earth.With so many plants,animals,and other creatures covering the planet,it can be toughto figure out what type of spider is moving up your leg or what kind of bird is flying by.A soon-to-be-launched Web site might help. An international team of researchers has announced thecreation of a Web-based Encyclopedia of Life(EoL).The project aims to catalog every species on Earth in asingle,easy-to-use reference guide.To get the encyclopedia started,the creators will use information from scientific databases that alreadyexist.And eventually,in special sections of the site,nonscientists with specialized knowledge will get to join in.Bird-watchers,for example,will be able to input which birds they've seen and where.The technologyfor this kind of tool has only recently become available.As the EoL develops, you might find it useful for school projects.The site will feature special pages forkids who are studying ecosystems（生态系统）in their neighborhoods. To make sure the encyclopedia isaccurate,scientists will review much of the information added to it. People who visit the site will be able tochoose to leave out pages that haven't been reviewed.Another convenient feature of the EoL is that you'll be able to pick the level of detail you see to matchyour interests,age,and current knowledge.If you wanted to learn about bears for a science class report,forexample,you could use the"novice"setting to get basic information about the animals.On the"expert" setting,on the other hand,you could get much more detailed information about the history,literature and exploration of bears.It now takes years for scientists to collect all the data they need to describe and analyze species.Thecreators of the Encyclopedia of Life hope that their new tool will speed that process.The goal of the creation of the EoL is to_______________.A:collect enough data to analyze the living species on EarthB:work out an easy-to-use catalog of every living species on EarthC:enlarge an existing Web site of the living species on EarthD:add new information to the existing databases of the living species on Earth
共用题干第二篇The Book of LifeSo far,scientists have named about 1.8 million living species,and that's just a fraction of what proba- bly exists on Earth.With so many plants,animals,and other creatures covering the planet,it can be toughto figure out what type of spider is moving up your leg or what kind of bird is flying by.A soon-to-be-launched Web site might help. An international team of researchers has announced thecreation of a Web-based Encyclopedia of Life(EoL).The project aims to catalog every species on Earth in asingle,easy-to-use reference guide.To get the encyclopedia started,the creators will use information from scientific databases that alreadyexist.And eventually,in special sections of the site,nonscientists with specialized knowledge will get to join in.Bird-watchers,for example,will be able to input which birds they've seen and where.The technologyfor this kind of tool has only recently become available.As the EoL develops, you might find it useful for school projects.The site will feature special pages forkids who are studying ecosystems（生态系统）in their neighborhoods. To make sure the encyclopedia isaccurate,scientists will review much of the information added to it. People who visit the site will be able tochoose to leave out pages that haven't been reviewed.Another convenient feature of the EoL is that you'll be able to pick the level of detail you see to matchyour interests,age,and current knowledge.If you wanted to learn about bears for a science class report,forexample,you could use the"novice"setting to get basic information about the animals.On the"expert" setting,on the other hand,you could get much more detailed information about the history,literature and exploration of bears.It now takes years for scientists to collect all the data they need to describe and analyze species.Thecreators of the Encyclopedia of Life hope that their new tool will speed that process.Which of the following statements is NOT true?A:Scientists will review every piece of the information added to the EoL.B:The EoL will be beneficial to school kids with its development.C:Scientists have cataloged only a small part of the living species on Earth.D:People with different interests and knowledge will in a way find the EoL useful.
共用题干第二篇The Book of LifeSo far,scientists have named about 1.8 million living species,and that's just a fraction of what proba- bly exists on Earth.With so many plants,animals,and other creatures covering the planet,it can be toughto figure out what type of spider is moving up your leg or what kind of bird is flying by.A soon-to-be-launched Web site might help. An international team of researchers has announced thecreation of a Web-based Encyclopedia of Life(EoL).The project aims to catalog every species on Earth in asingle,easy-to-use reference guide.To get the encyclopedia started,the creators will use information from scientific databases that alreadyexist.And eventually,in special sections of the site,nonscientists with specialized knowledge will get to join in.Bird-watchers,for example,will be able to input which birds they've seen and where.The technologyfor this kind of tool has only recently become available.As the EoL develops, you might find it useful for school projects.The site will feature special pages forkids who are studying ecosystems（生态系统）in their neighborhoods. To make sure the encyclopedia isaccurate,scientists will review much of the information added to it. People who visit the site will be able tochoose to leave out pages that haven't been reviewed.Another convenient feature of the EoL is that you'll be able to pick the level of detail you see to matchyour interests,age,and current knowledge.If you wanted to learn about bears for a science class report,forexample,you could use the"novice"setting to get basic information about the animals.On the"expert" setting,on the other hand,you could get much more detailed information about the history,literature and exploration of bears.It now takes years for scientists to collect all the data they need to describe and analyze species.Thecreators of the Encyclopedia of Life hope that their new tool will speed that process.The word"novice"in Paragraph 5 could be best replaced by_______________.A:beginnerB:scientistC:creatorD:expert
Text 3 Up until a few decades ago,our visions of the future were largely-though by no means uniformly-glowingly positive.Science and technology would cure all the ills of humanity,leading to lives of fulfillment and opportunity for all.Now utopia has grown unfashionable,as we have gained a deeper appreciation of the range of threats facing us,from asteroid strike to epidemic flu and to climate change.You might even be tempted to assume that humanity has little future to look forward to.But such gloominess is misplaced.The fossil record shows that many species have endured for millions of years-so why shouldn't we?Take a broader look at our species'place in the universe,and it becomes clear that we have an excellent chance of surviving for tens,if not hundreds,of thousands of years.Look up Homo sapiens in the"Red List"of threatened species of the International Union for the Conversation of Nature（IUCN）,and you will read:"Listed as Least Concern as the species is very widely distributed,adaptable,currently increasing,and there are no major threats resulting in an overall population decline."So what does our deep future hold?A growing number of researchers and organisations are now thinking seriously about that question.For example,the Long Now Foundation has its flagship project a medical clock that is designed to still be marking time thousands of years hence.Perhaps willfully,it may be easier to think about such lengthy timescales than about the more immediate future.The potential evolution of today's technology,and its social consequences,is dazzlingly complicated,and it's perhaps best left to science fiction writers and futurologists to explore the many possibilities we can envisage.That's one reason why we have launched Arc,a new publication dedicated to the near future.But take a longer view and there is a surprising amount that we can say with considerable assurance.As so often,the past holds the key to the future:we have now identified enough of the long-term patterns shaping the history of the planet,and our species,to make evidence-based forecasts about the situations in which our descendants will find themselves.This long perspective makes the pessimistic view of our prospects seem more likely to be a passing fad.To be sure,the future is not all rosy.But we are now knowledgeable enough to reduce many of the risks that threatened the existence of earlier humans,and to improve the lot of those to come.31.Our vision of the future used to be inspired byA.our desire for lives of fulfillmentB.our faith in science and technologyC.our awareness of potential risksD.our belief in equal opportunity
共用题干Music Used as a Healing Therapy1 .Music has long been used to treat patients suffering from different problems.In 400 BC,its healing properties were documented by the ancient Greeks. More recently,in both world wars in the last century, medical workers used music therapy（疗法）with people suf-fering from trauma（外伤）.Currently, it is used as a treatment for many diseases, such as cancer,and it has also been used with patients with long-term pain and learning disabilities.2 .There is growing evidence that music can caused physical changes to the body which can im-prove our health. In the Welcome Trust study,which took place over three years at the Chelsea and Westminster hospital in London,patients were asked to listen to musical perform-ances. As a result,it was found that stress levels were significantly reduced,recovery times were improved,and fewer drugs were needed.3. These very positive results are partly due to general well-being（良好的健康状况）.It is already accepted that when people feel happy and have a positive approach to life,they are more likely to feel better and recover from disease quickly. Music increases this feeling of joy and adds to the recovery process.4 .However,not all these benefits can be attributed to an increase in general well-being. Music has other effects which have not yet been understood. According to Professor Robert-son,a scientist and musician,some effects of music are mysterious and are,therefore,being investigated further. It has been suggested that the sounds and rhythms of music help stimu-late the brain and send electrical messages to the muscles.5 .Science,however,demands facts and hard evidence. Many in the medical profession have not yet recognized the healing benefits of music,since reports have been based mainly on various stories of evidence. These new studies could provide proof to doctors that music is a suitable treatment for many conditions. One day doctors may even “prescribe”（开处方） music,but that could be a long time in the future.Those who always look on the bright side of life are more likely to______.A: recover from disease quicklyB: there is not enough hard evidenceC: use their minds activelyD: it improves general well-beingE: listen to musical performancesF: it brings many other benefits
共用题干Music Used as a Healing Therapy1 .Music has long been used to treat patients suffering from different problems.In 400 BC,its healing properties were documented by the ancient Greeks. More recently,in both world wars in the last century, medical workers used music therapy（疗法）with people suf-fering from trauma（外伤）.Currently, it is used as a treatment for many diseases, such as cancer,and it has also been used with patients with long-term pain and learning disabilities.2 .There is growing evidence that music can caused physical changes to the body which can im-prove our health. In the Welcome Trust study,which took place over three years at the Chelsea and Westminster hospital in London,patients were asked to listen to musical perform-ances. As a result,it was found that stress levels were significantly reduced,recovery times were improved,and fewer drugs were needed.3. These very positive results are partly due to general well-being（良好的健康状况）.It is already accepted that when people feel happy and have a positive approach to life,they are more likely to feel better and recover from disease quickly. Music increases this feeling of joy and adds to the recovery process.4 .However,not all these benefits can be attributed to an increase in general well-being. Music has other effects which have not yet been understood. According to Professor Robert-son,a scientist and musician,some effects of music are mysterious and are,therefore,being investigated further. It has been suggested that the sounds and rhythms of music help stimu-late the brain and send electrical messages to the muscles.5 .Science,however,demands facts and hard evidence. Many in the medical profession have not yet recognized the healing benefits of music,since reports have been based mainly on various stories of evidence. These new studies could provide proof to doctors that music is a suitable treatment for many conditions. One day doctors may even “prescribe”（开处方） music,but that could be a long time in the future.Researchers have found that patients'stress levels decrease when they______.A: recover from disease quicklyB: there is not enough hard evidenceC: use their minds activelyD: it improves general well-beingE: listen to musical performancesF: it brings many other benefits
共用题干Music Used as a Healing Therapy1 .Music has long been used to treat patients suffering from different problems.In 400 BC,its healing properties were documented by the ancient Greeks. More recently,in both world wars in the last century, medical workers used music therapy（疗法）with people suf-fering from trauma（外伤）.Currently, it is used as a treatment for many diseases, such as cancer,and it has also been used with patients with long-term pain and learning disabilities.2 .There is growing evidence that music can caused physical changes to the body which can im-prove our health. In the Welcome Trust study,which took place over three years at the Chelsea and Westminster hospital in London,patients were asked to listen to musical perform-ances. As a result,it was found that stress levels were significantly reduced,recovery times were improved,and fewer drugs were needed.3. These very positive results are partly due to general well-being（良好的健康状况）.It is already accepted that when people feel happy and have a positive approach to life,they are more likely to feel better and recover from disease quickly. Music increases this feeling of joy and adds to the recovery process.4 .However,not all these benefits can be attributed to an increase in general well-being. Music has other effects which have not yet been understood. According to Professor Robert-son,a scientist and musician,some effects of music are mysterious and are,therefore,being investigated further. It has been suggested that the sounds and rhythms of music help stimu-late the brain and send electrical messages to the muscles.5 .Science,however,demands facts and hard evidence. Many in the medical profession have not yet recognized the healing benefits of music,since reports have been based mainly on various stories of evidence. These new studies could provide proof to doctors that music is a suitable treatment for many conditions. One day doctors may even “prescribe”（开处方） music,but that could be a long time in the future.Many doctors don't believe that music can treat diseases because______.A: recover from disease quicklyB: there is not enough hard evidenceC: use their minds activelyD: it improves general well-beingE: listen to musical performancesF: it brings many other benefits
共用题干第二篇The Book of LifeSo far, scientists have named about 1.8 million living species（物种）,and that's just a small part of what probably exists on Earth.With so many plants,animals,and other creatures covering the planet,it can be tough to figure out what type of spider is moving up your leg or what kind of bird is flying by.A soon-to-be-launched Web site mighit help. An international team of researchers has announced the creation of a Web-based Encyclopedia（百科全书）of Life(EoL).The project aims to catalog every species on Earth in a single,easy-to-use referenice guide.To get the encyclopedia started,the creators will use information from scientific databases（数据库）that already exist. And eventually , in special sections of the site , nonscientists with specialized（专门的） knowledge will get to join in Bird-watchers,for example,will be able to input which birds they'ye seen and where.The technology for this kind of tool has only recently become available.As the EoL develops,you might find it useful for school projects.The site will feature special pages for kids who are studying ecosystems（生态系统）in their neighborhoods. To make sure the encyclopedia is accurate,scientists will review much of the information added to it.People who visit the site will be able tochoose to leave out pages that haven't been reviewed.Another convenient feature of the EoL is that you'11 be able to pick the level of detail you see to match your interests,age,and current knowledge.If you wanted to learn about bears for a science class report,for example,you could use the"novice"setting to get basic information about the animals.On the"expert" setting,on the other hand,you could get much more detailed information about the history,literature,andexploration of bears.It now takes years for scientists to collect all the data they need to describe and analyze species.The creators of the Encyclopedia of Life hope that their new tool will speed that process.The goal of the creation of the EoL is to________.A:collect enough data to analyze the living species on EarthB:enlarge an existing Web site of the living species on EarthC:work out an easy-to-use catalog of every living species on EarthD:add new information to the existing databases of the living species on Earth
共用题干第二篇The Book of LifeSo far, scientists have named about 1.8 million living species（物种）,and that's just a small part of what probably exists on Earth.With so many plants,animals,and other creatures covering the planet,it can be tough to figure out what type of spider is moving up your leg or what kind of bird is flying by.A soon-to-be-launched Web site mighit help. An international team of researchers has announced the creation of a Web-based Encyclopedia（百科全书）of Life(EoL).The project aims to catalog every species on Earth in a single,easy-to-use referenice guide.To get the encyclopedia started,the creators will use information from scientific databases（数据库）that already exist. And eventually , in special sections of the site , nonscientists with specialized（专门的） knowledge will get to join in Bird-watchers,for example,will be able to input which birds they'ye seen and where.The technology for this kind of tool has only recently become available.As the EoL develops,you might find it useful for school projects.The site will feature special pages for kids who are studying ecosystems（生态系统）in their neighborhoods. To make sure the encyclopedia is accurate,scientists will review much of the information added to it.People who visit the site will be able tochoose to leave out pages that haven't been reviewed.Another convenient feature of the EoL is that you'11 be able to pick the level of detail you see to match your interests,age,and current knowledge.If you wanted to learn about bears for a science class report,for example,you could use the"novice"setting to get basic information about the animals.On the"expert" setting,on the other hand,you could get much more detailed information about the history,literature,andexploration of bears.It now takes years for scientists to collect all the data they need to describe and analyze species.The creators of the Encyclopedia of Life hope that their new tool will speed that process.Which of the following statements is NOT true?A:The EoL will be beneficial to school kids with its development.B:Scientists have cataloged only a small part of the living species on Earth.C:People with different interests and knowledge will in a way find the EoL useful.D:Scientists will review every piece of the information added to the EoL.
共用题干第二篇The Book of LifeSo far, scientists have named about 1.8 million living species（物种）,and that's just a small part of what probably exists on Earth.With so many plants,animals,and other creatures covering the planet,it can be tough to figure out what type of spider is moving up your leg or what kind of bird is flying by.A soon-to-be-launched Web site mighit help. An international team of researchers has announced the creation of a Web-based Encyclopedia（百科全书）of Life(EoL).The project aims to catalog every species on Earth in a single,easy-to-use referenice guide.To get the encyclopedia started,the creators will use information from scientific databases（数据库）that already exist. And eventually , in special sections of the site , nonscientists with specialized（专门的） knowledge will get to join in Bird-watchers,for example,will be able to input which birds they'ye seen and where.The technology for this kind of tool has only recently become available.As the EoL develops,you might find it useful for school projects.The site will feature special pages for kids who are studying ecosystems（生态系统）in their neighborhoods. To make sure the encyclopedia is accurate,scientists will review much of the information added to it.People who visit the site will be able tochoose to leave out pages that haven't been reviewed.Another convenient feature of the EoL is that you'11 be able to pick the level of detail you see to match your interests,age,and current knowledge.If you wanted to learn about bears for a science class report,for example,you could use the"novice"setting to get basic information about the animals.On the"expert" setting,on the other hand,you could get much more detailed information about the history,literature,andexploration of bears.It now takes years for scientists to collect all the data they need to describe and analyze species.The creators of the Encyclopedia of Life hope that their new tool will speed that process."Spider" and "bird" mentioned in Paragraph 1 are examples to illustrate________.A:animals are people’s friendsB:there are numerous living species on EarthC:it is easy to see spiders and birdsD:there are many types of spiders and birds
共用题干Some Things We Know About LanguageMany things about language are a mystery,and many will always remain so.But some things we do know.First,we know that all human beings have a language of some sort. There is no race of men anywhere on earth so backward that it has no language,no set of speech sounds by which the people communicate with one another. Furthermore,in historical times,there has never been a race of men without a language.Second,there is no such thing as a primitive language.There are many people whose cultures are undeveloped,who are,as we say,uncivilized,but the languages they speak are not primitive .In all known languages we can see complexities that must have been tens of thousands of years in developing.This has not always been well understood;indeed,the direct contrary has often been stated.Popular ideas of the language of the American Indians will illustrate.Many people have supposed that the Indians communicated in a very primitive system of noises.Study has proved this to be nonsense .There are,or were,hundreds of American Indian languages,and all of them turn out to be very complicated and very old.They are certainly different from the languages that most of us are familiar with,but they are no more primitive than English and Greek.A third thing we know about language is that all languages are perfectly adequate. That is, each one is a perfect means of expressing the culture of the people who speak the language.Finally,we know that language changes.It is natural and normal for language to change;the only languages which do not change are the dead ones.This is easy to understand if we look backward in time.Change goes on in all aspects of language.Grammatical teatures change as do speech sounds,and changes in vocabulary are sometimes very extensive and may occur very rap-idly. Vocabulary is the least stable part of any language. The author has used American Indian languages as an example to show that they are______.A: just as old as some well-known languagesB: just as sophisticated as some well-known languagesC: more developed than some well-known languagesD: more complex than some well-known languages
共用题干Ants as a Barometer of Ecological ChangeAt picnics,ants are pests.But they have their uses.In industries such as mining,farming and forestry , they can help gauge（测定）the health of the environment by just crawling around and being antsy（坐立不安）.It has been recognized for decades that ants—which are highly sensitive to ecological change—can provide a near-perfect barometer（气压计）of the state of an ecosystem. Only certain species,for instance,will continue to thrive at a forest site that has been cleared of trees. ______(46)And still others will move in and take up residence.By looking at which species populate a deforested area,scientists can determine how“stressed”the land is.______(47)Ants are used simply because they are so common and comprise（构成）so many species.Where mine sites are being restored,for example,some ant species will recolonize（重新移居到.……）the stripped land more quickly than others.______ (48 ) Australian mining compa- ny Capricorn Coal Management has been successfully using ant surveys for years to determine the rate of recovery of land that it is replanting near its German Creek mine in Queensland.Ant surveys also have been used with mine-site recovery projects in Africa and Brazil,where warm climates encourage dense and diverse ant populations.“We found it worked extremely well there,”says Jonathan Major,a professor of environmental biology.Yet the surveys are perfectly suited to climates throughout Asia,he says,because ants are so common throughout the region.As Major puts it:“That's the great thing about ants.”Ant surveys are so highly regarded as ecological indicators（指示器）that governments world-wide accept their results when assessing（评估）the environmental impact of mining and tree har- vesting.______(49）.Why not?Because many companies can't afford the expense or the laboratory time needed to sift（详审）results for a comprehensive survey. The cost stems,also, from the scarcity（缺乏）of ant specialists.______(50)______(47)A:This allowed scientists to gauge the pace and progress of the ecological recovery.B:Yet in other businesses,such as farming and property development,ant surveys aren't used widely.C: Employing those people are expensive.D: They do this by sorting the ants,counting their numbers and comparing the results with those of earlier surveys.E: The evolution of ant species may have a strong impact on our ecosystem.F: Others will die out for lack of food.
A system administrator has been instructed to verify that all filesets have all required requisites and are completely installed. Which command will provide this information？（）A、lslppB、lppchkC、instfixD、installp
A System p administrator has been instructed to verify that all filesets have all required requisitesand are completely installed. Which of the following commands will provide this information（）A、lslppB、lppchkC、geninstallD、installp
单选题A System p administrator has been instructed to verify that all filesets have all required requisitesand are completely installed. Which of the following commands will provide this information（）AlslppBlppchkCgeninstallDinstallp
单选题A great number of national parks have been set up to________ endangered species from extinction.AconserveBpreserveCreserveDobserve
单选题A system administrator has been instructed to verify that all filesets have all required requisites and are completely installed. Which command will provide this information？（）AlslppBlppchkCinstfixDinstallp
单选题Which of the following best expresses the main idea of Paragraph 2?ABecause of their characteristics as double organisms, it is difficult to classify lichens.BOver 15,000 varieties of lichens have been identified.CDouble organisms should always be classified as separate species.DTaxonomists always find it difficult to classify new species of plants.
单选题According to lines 50－58 of Passage 2, microevolution ______.Ahas never actually been observed, but is believed to be theoretically possibleBis the series of small changes that transforms one species into anotherClacks evidence, and therefore should not be considered a scientific factDis an evolutionary process involving small changes within a speciesEoccurs wherever there are environmental changes in a species' habitat
单选题The food we eat seems to have profound effects on our health.Although science has made enormous steps in making food more fit to eat ,it has, at the same time,made many foods unfit to eat. Some research has shown that perhaps eighty percent of all human illnesses are related to diet and forty percent of cancer is related to the diet as well,especially cancer of the colon. Different cultures are more likely to cause certain different illnesses because of the food that is characteristic in these cultures. That food is related to illness is nto a new discovery. In 1945, about 35 years ago, government researchers realized that nitrates, commonly used to preserve color in meats,and other food additives,caused cancer. Yet, these carcinogenic additives remain in our food, and it becomes more difficult all the time to know which things on the packaging labels of processed food are helpful or harmful. The additives which we eat are not all so direct. Farmers often give penicillin to beef and living animals, and because of this ,penicillin has been found in the milk of treated cow. Sometimes similar drugs are given to animals not for medical purposes,but for financial reasons. The farmers are simply trying to fatten the animals in order to obtain a higher price on the market. Although the Food and Drug Administration(FDA) has tried repeatedly to control these procedures, the practices continue.How has science done something harmful to mankind?（）ABecause of science , diseases caused by polluted food haven been virtually eliminated.BIt has caused a lack of information concerning the value of food.CBecause of the application of science,some potentially harmful substances have been added to food.DThe scientists have preserved the color of meats,but not of vegetables.
单选题A frequently cited example of the endangered species is the panda.AworriedBneglectedCreducedDmentioned
问答题Despite the basic biological, chemical, and physical similarities found in all living things, a diversity of life exists not only among and between species but also within every natural population. The phenomenon of diversity has had a long history of study because so many of the variations that exist in nature are visible to the eye. 1) It has been suggested that sexual reproduction became the dominant type of reproduction among organisms because of its inherent advantage of variability, which is the mechanism that enables a species to adjust to changing conditions.New variations are potentially present in genetic differences, but how preponderant a variation becomes in a gene pool depends upon the number of offspring the mutants or variants produce (differential reproduction). 2)It is possible for a genetic novelty (new variation) to spread in time to all members of a population, especially if the novelty enhances the population’s chances for survival in the environment in which it exists.Thus, when a species is introduced into a new habitat, it either adapts to the change by natural selection or by some other evolutionary mechanism or else it eventually dies off. Because each new habitat means new adaptations, habitat changes have been responsible for the millions of different kinds of species and for the heterogeneity within each species. The total number of animal and plant species is estimated at between 2,000,000 and 4,500,000; authoritative estimates of the number of extinct species range from 15,000,000 up to 16,000,000,000. 3)Although the use of classification as a means of producing some kind of order out of this staggering number of different types of organisms appears as early as the book of Genesis—with references to cattle, beasts, fowl, creeping things, trees, etc.—the first scientific attempt at classification is attributed to the Greek philosopher Aristotle, who tried to establish a system that would indicate the relationship of all things to each other.He arranged everything along a scale, or “ladder of nature”, with nonliving things at the bottom; plants were placed below animals, and man was at the top. 4)Other schemes that have been used for grouping species include large anatomical similarities, such as wings or fins, which indicate a natural relationship, and also similarities in reproductive structures. 5)At the present time taxonomy is based on two major assumptions: one is that similar body construction can be used as a criterion for a classification grouping; the other is that, in addition to structural similarities, evolutionary and molecular relationships between organisms can be used as a means for determining classification.
单选题The passage is focused on _____.Ahow the scientists tried to protect endangered speciesBhow the symbolic endangered species has been chosenCthe relation between global warming and endangered speciesDthe problems in and the future of endangered species protection