单选题Elephants are afraid of bees because ______.Athey are too small to catchBthere are too many of them in the forestCbees can attach certain parts of the elephant’s bodyDbees can kill elephants
单选题
Elephants are afraid of bees because ______.
A
they are too small to catch
B
there are too many of them in the forest
C
bees can attach certain parts of the elephant’s body
D
bees can kill elephants
参考解析
解析：
录音中指出虽然大象皮很厚，但是它们耳朵后面、鼻子下边和眼睛周围比较敏感，由此可知大象之所以害怕蜜蜂是因为蜜蜂可以附到大象身体的某些部位，因此选C。
录音中指出虽然大象皮很厚，但是它们耳朵后面、鼻子下边和眼睛周围比较敏感，由此可知大象之所以害怕蜜蜂是因为蜜蜂可以附到大象身体的某些部位，因此选C。
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共用题干What's Killing the BatsFirst it was bees.Now it is bats.Biologists in America are working hard to discover the cause of the mysterious deaths of tens of thousands of bats in the northeastern part of the country.Most of the bats affected are the common little brown bats(Myotis lucifugus,)but other species, such as the long-eared bat,the small-footed bat,the eastern pipistrelle,and the Indiana bat have also been affected. In some caves,more than 90 percent of the bat populations have died.One possibility is disease. A white fungus（真菌）known as fusarium has been found on the noses of both living and dead bats.However,scientists don't know if the fungus is the primary cause of death,a secondary cause of death,or not a cause at all,but the result of some other conditions.Another possible cause is a lack of food.For example,bats typically eat a large number of moths（蛾）,and in some states such as New York,the number of moths has been declining in recent years. if bats can't eat enough food,they starve to death.Still other scientists believe that global warming is to blame.Warmer temperatures in recent years have been waking up hibernating（冬眠）bats earlier than usual. If bats break their hiberna- lion at the wrong time,they might not find their expected food sources. The weather might also turn cold again and weaken or kill the bats.Scientists might not agree on the causes of the bat die-off, but they do agree on the conse- quences. Bats are an important predator of mosquitoes:a single brown bat can eat 1,000 or more insects in an hour. They also eat beetles and other insects that damage plant crops.If there aren't enough bats,damage will be great from the insects they eat. While bats live a long time for their size-the little brown bat can live for more than 30 years-a female bat has only one baby per year,so bat populations grow slowly. Many bat species in the United States are already protected or endangered.How can you help?Do not disturb sleeping or nesting bats.If you discover bats that seem to be sick or that are dead,contact your local Fish& Wildlife Department with the details.However, be careful not to touch the animals. What does the first sentence in Paragraph 1 mean?A: Bees have been dying mysteriously.B: The first article on the website is about bees.C: Bees usually die before bats.D: It was bees that caused the deaths of bats.
共用题干第二篇Don ' t Count on Dung" Conservationists（自然保护主义者）may be miscalculating the numbers of the threatened animals such as elephants."say African and American researchers.The error occurs because of a flaw in the way that they estimate animal numbers from the piles of dung（粪）the creatures leave behind.The mistake could lead researchers to think that there are twice as many elephants as there really are in some regions,according to Andrew Plumptre of the Wildlife Conservation Society(WCS)in New York.Biologist Katy Payne of Cornell University in Ithaca,New York,agrees."We really need to know ele- phant numbers and the evidence that we have is quite indirect,"says Payne,who electronically tracks elephants.Counting elephants from planes is impossible in the vast rainforests of Central Africa. So researchers of- ten estimate elephant numbers by counting dung piles in a given area.They also need to know the rate at which dung decays.Because it's extremely difficult to determine these rates,researchers counting elephants in one region tend to rely on standard decay rates established elsewhere.But researchers at the WCS have found that this decay rate varies from region to region depending on the climate and environment. " Using the wrong values can lead the census astray（离开正道）,"says Plumptre.He and his colleague Anthony Chifu Nchanji studied decaying elephant dung in the forests of Came- roon.They found that the dung decayed between 55 and 65 per cent more slowly than the dung in therainforests of neighbouring Gabon.If researchers use decay rates from Gabon to count elephants in Cameroon, they would probably find more elephants than are actually around."This could mean estimates in Cameroon are at least twice as high as those derived from decay rates calculated locally,"says Plumptre."However accurate your dung density estimate might be,the decay rate can severely affect the result."Plumptre also says that the dung-pile census should be carried out over a region similar in size to an ele- phant's natural range."The usual technique of monitoring only small,protected areas distorts numbers be-cause elephants move in and out of these regions,"he says."If the elephant population increases within the protected area,you cannot determine whether it is a real increase or whether it is due to elephants moving in because they are being poached（入侵偷猎）outside."Plumptre says that similar problems may also affect other animal census studies that rely on indirect evi-- dence such as nests,tracks or burrows（地洞）.Piles of dung can't be relied upon when it comes to estimating elephant numbers because_______.A:they are different in sizeB:they scatter all over the regionC:they are different in decay rateD:they are different in quality
共用题干第二篇Don ' t Count on Dung" Conservationists（自然保护主义者）may be miscalculating the numbers of the threatened animals such as elephants."say African and American researchers.The error occurs because of a flaw in the way that they estimate animal numbers from the piles of dung（粪）the creatures leave behind.The mistake could lead researchers to think that there are twice as many elephants as there really are in some regions,according to Andrew Plumptre of the Wildlife Conservation Society(WCS)in New York.Biologist Katy Payne of Cornell University in Ithaca,New York,agrees."We really need to know ele- phant numbers and the evidence that we have is quite indirect,"says Payne,who electronically tracks elephants.Counting elephants from planes is impossible in the vast rainforests of Central Africa. So researchers of- ten estimate elephant numbers by counting dung piles in a given area.They also need to know the rate at which dung decays.Because it's extremely difficult to determine these rates,researchers counting elephants in one region tend to rely on standard decay rates established elsewhere.But researchers at the WCS have found that this decay rate varies from region to region depending on the climate and environment. " Using the wrong values can lead the census astray（离开正道）,"says Plumptre.He and his colleague Anthony Chifu Nchanji studied decaying elephant dung in the forests of Came- roon.They found that the dung decayed between 55 and 65 per cent more slowly than the dung in therainforests of neighbouring Gabon.If researchers use decay rates from Gabon to count elephants in Cameroon, they would probably find more elephants than are actually around."This could mean estimates in Cameroon are at least twice as high as those derived from decay rates calculated locally,"says Plumptre."However accurate your dung density estimate might be,the decay rate can severely affect the result."Plumptre also says that the dung-pile census should be carried out over a region similar in size to an ele- phant's natural range."The usual technique of monitoring only small,protected areas distorts numbers be-cause elephants move in and out of these regions,"he says."If the elephant population increases within the protected area,you cannot determine whether it is a real increase or whether it is due to elephants moving in because they are being poached（入侵偷猎）outside."Plumptre says that similar problems may also affect other animal census studies that rely on indirect evi-- dence such as nests,tracks or burrows（地洞）.According to Plumptre,the region over which a dung-pile census is carried out should be_________.A:small enoughB:well protectedC:carefully monitoredD:large enough
共用题干第二篇Don ' t Count on Dung" Conservationists（自然保护主义者）may be miscalculating the numbers of the threatened animals such as elephants."say African and American researchers.The error occurs because of a flaw in the way that they estimate animal numbers from the piles of dung（粪）the creatures leave behind.The mistake could lead researchers to think that there are twice as many elephants as there really are in some regions,according to Andrew Plumptre of the Wildlife Conservation Society(WCS)in New York.Biologist Katy Payne of Cornell University in Ithaca,New York,agrees."We really need to know ele- phant numbers and the evidence that we have is quite indirect,"says Payne,who electronically tracks elephants.Counting elephants from planes is impossible in the vast rainforests of Central Africa. So researchers of- ten estimate elephant numbers by counting dung piles in a given area.They also need to know the rate at which dung decays.Because it's extremely difficult to determine these rates,researchers counting elephants in one region tend to rely on standard decay rates established elsewhere.But researchers at the WCS have found that this decay rate varies from region to region depending on the climate and environment. " Using the wrong values can lead the census astray（离开正道）,"says Plumptre.He and his colleague Anthony Chifu Nchanji studied decaying elephant dung in the forests of Came- roon.They found that the dung decayed between 55 and 65 per cent more slowly than the dung in therainforests of neighbouring Gabon.If researchers use decay rates from Gabon to count elephants in Cameroon, they would probably find more elephants than are actually around."This could mean estimates in Cameroon are at least twice as high as those derived from decay rates calculated locally,"says Plumptre."However accurate your dung density estimate might be,the decay rate can severely affect the result."Plumptre also says that the dung-pile census should be carried out over a region similar in size to an ele- phant's natural range."The usual technique of monitoring only small,protected areas distorts numbers be-cause elephants move in and out of these regions,"he says."If the elephant population increases within the protected area,you cannot determine whether it is a real increase or whether it is due to elephants moving in because they are being poached（入侵偷猎）outside."Plumptre says that similar problems may also affect other animal census studies that rely on indirect evi-- dence such as nests,tracks or burrows（地洞）.Why do researchers estimate elephant numbers in an area by counting dung piles?A:Because elephants are difficult to catch.B:Because it is not possible to count elephants from a plane.C:Because it is not possible to keep track of elephants.D:Because elephants are shy animals.
共用题干第二篇Don't Count on DungConservationists（自然保护主义者）may be miscalculating the numbers of the threatened animals such as elephants,say African and American researchers.The error occurs because of a flaw in the way they estimate animal numbers from the piles of dung （粪）the creatures leave behind.The mistake could lead researchers to think that there are twice as many elephants as there really are in some regions,according to Andrew Plumptre of the Wildlife Conservation Society(WCS)in New York.Biologist Katy Payne of Cornell University in Ithaca,New York,agrees.“We really need to know elephant numbers and the evidence that we have is quite indirect,"says Payne,who electronically tracks elephants.Counting elephants from planes is impossible in the vast rainforests of Central Africa.So researchers often estimate elephant numbers by counting dung piles in a given area.They also need to know the rate at which dung decays.Because it's extremely difficult to determine these rates,however,researchers counting elephants in one region tend to rely on standard decay rates established elsewhere.But researchers at the WCS have found that this decay rate varies from region to region depending on the climate and environment.Using the wrong values can lead the censusastray（离开正道）,says Plumptre.He and his colleague Anthony Chifu Nchanji studied decaying elephant dung in the forests of Cameroon.They found that the dung decayed between 55 and 65 per cent more slowly than the dung in the rainforests of neighbouring Gabon.If researchers use decay rates from Gabon to count elephants in Cameroon,they would probably find more elephants than are actually around.This could mean estimates in Cameroon are at least twice as high as those derived from decay rates calculated locally,says Plumptre."However accurate your dung densityestimate might be,the decay rate can severely affect the result.''Plumptre also says that the dung-pile census should be carried out over a region similar in size to an elephant's natural range.The usual technique of monitoring only small, protected areas distorts numbers because elephants move in and out of these regions,he says."If the elephant population increases within the protected area,you can not determine whether it is a real increase or whether it is due to elephants moving in because they are being poached（入侵偷猎）outside."Plumptre says that similar problems may also affect other animal census studies that rely on indirect evidence such as nests,tracks or burrows（地洞）.Why do researchers estimate elephant numbers in an area by counting dung piles?A:Because elephants are difficult to catch.B:Because it is not possible to count elephants from a plane.C:Because it is not possible to keep track of elephants.D:Because elephants are shy animals.
共用题干第二篇Don't Count on DungConservationists（自然保护主义者）may be miscalculating the numbers of the threatened animals such as elephants,say African and American researchers.The error occurs because of a flaw in the way they estimate animal numbers from the piles of dung （粪）the creatures leave behind.The mistake could lead researchers to think that there are twice as many elephants as there really are in some regions,according to Andrew Plumptre of the Wildlife Conservation Society(WCS)in New York.Biologist Katy Payne of Cornell University in Ithaca,New York,agrees.“We really need to know elephant numbers and the evidence that we have is quite indirect,"says Payne,who electronically tracks elephants.Counting elephants from planes is impossible in the vast rainforests of Central Africa.So researchers often estimate elephant numbers by counting dung piles in a given area.They also need to know the rate at which dung decays.Because it's extremely difficult to determine these rates,however,researchers counting elephants in one region tend to rely on standard decay rates established elsewhere.But researchers at the WCS have found that this decay rate varies from region to region depending on the climate and environment.Using the wrong values can lead the censusastray（离开正道）,says Plumptre.He and his colleague Anthony Chifu Nchanji studied decaying elephant dung in the forests of Cameroon.They found that the dung decayed between 55 and 65 per cent more slowly than the dung in the rainforests of neighbouring Gabon.If researchers use decay rates from Gabon to count elephants in Cameroon,they would probably find more elephants than are actually around.This could mean estimates in Cameroon are at least twice as high as those derived from decay rates calculated locally,says Plumptre."However accurate your dung densityestimate might be,the decay rate can severely affect the result.''Plumptre also says that the dung-pile census should be carried out over a region similar in size to an elephant's natural range.The usual technique of monitoring only small, protected areas distorts numbers because elephants move in and out of these regions,he says."If the elephant population increases within the protected area,you can not determine whether it is a real increase or whether it is due to elephants moving in because they are being poached（入侵偷猎）outside."Plumptre says that similar problems may also affect other animal census studies that rely on indirect evidence such as nests,tracks or burrows（地洞）.According to Plumptre,the region over which a dung-pile census is carried out should beA:small enough.B:well protected.C:carefully monitored.D:large enough.
共用题干第二篇Don't Count on DungConservationists（自然保护主义者）may be miscalculating the numbers of the threatened animals such as elephants,say African and American researchers.The error occurs because of a flaw in the way they estimate animal numbers from the piles of dung （粪）the creatures leave behind.The mistake could lead researchers to think that there are twice as many elephants as there really are in some regions,according to Andrew Plumptre of the Wildlife Conservation Society(WCS)in New York.Biologist Katy Payne of Cornell University in Ithaca,New York,agrees.“We really need to know elephant numbers and the evidence that we have is quite indirect,"says Payne,who electronically tracks elephants.Counting elephants from planes is impossible in the vast rainforests of Central Africa.So researchers often estimate elephant numbers by counting dung piles in a given area.They also need to know the rate at which dung decays.Because it's extremely difficult to determine these rates,however,researchers counting elephants in one region tend to rely on standard decay rates established elsewhere.But researchers at the WCS have found that this decay rate varies from region to region depending on the climate and environment.Using the wrong values can lead the censusastray（离开正道）,says Plumptre.He and his colleague Anthony Chifu Nchanji studied decaying elephant dung in the forests of Cameroon.They found that the dung decayed between 55 and 65 per cent more slowly than the dung in the rainforests of neighbouring Gabon.If researchers use decay rates from Gabon to count elephants in Cameroon,they would probably find more elephants than are actually around.This could mean estimates in Cameroon are at least twice as high as those derived from decay rates calculated locally,says Plumptre."However accurate your dung densityestimate might be,the decay rate can severely affect the result.''Plumptre also says that the dung-pile census should be carried out over a region similar in size to an elephant's natural range.The usual technique of monitoring only small, protected areas distorts numbers because elephants move in and out of these regions,he says."If the elephant population increases within the protected area,you can not determine whether it is a real increase or whether it is due to elephants moving in because they are being poached（入侵偷猎）outside."Plumptre says that similar problems may also affect other animal census studies that rely on indirect evidence such as nests,tracks or burrows（地洞）.The word "threatened" in the first sentence of the first paragraph could be best replaced byA:"endangered".B:"frightened".C:"killed".D:"angered".
共用题干第二篇Don't Count on DungConservationists（自然保护主义者）may be miscalculating the numbers of the threatened animals such as elephants,say African and American researchers.The error occurs because of a flaw in the way they estimate animal numbers from the piles of dung （粪）the creatures leave behind.The mistake could lead researchers to think that there are twice as many elephants as there really are in some regions,according to Andrew Plumptre of the Wildlife Conservation Society(WCS)in New York.Biologist Katy Payne of Cornell University in Ithaca,New York,agrees.“We really need to know elephant numbers and the evidence that we have is quite indirect,"says Payne,who electronically tracks elephants.Counting elephants from planes is impossible in the vast rainforests of Central Africa.So researchers often estimate elephant numbers by counting dung piles in a given area.They also need to know the rate at which dung decays.Because it's extremely difficult to determine these rates,however,researchers counting elephants in one region tend to rely on standard decay rates established elsewhere.But researchers at the WCS have found that this decay rate varies from region to region depending on the climate and environment.Using the wrong values can lead the censusastray（离开正道）,says Plumptre.He and his colleague Anthony Chifu Nchanji studied decaying elephant dung in the forests of Cameroon.They found that the dung decayed between 55 and 65 per cent more slowly than the dung in the rainforests of neighbouring Gabon.If researchers use decay rates from Gabon to count elephants in Cameroon,they would probably find more elephants than are actually around.This could mean estimates in Cameroon are at least twice as high as those derived from decay rates calculated locally,says Plumptre."However accurate your dung densityestimate might be,the decay rate can severely affect the result.''Plumptre also says that the dung-pile census should be carried out over a region similar in size to an elephant's natural range.The usual technique of monitoring only small, protected areas distorts numbers because elephants move in and out of these regions,he says."If the elephant population increases within the protected area,you can not determine whether it is a real increase or whether it is due to elephants moving in because they are being poached（入侵偷猎）outside."Plumptre says that similar problems may also affect other animal census studies that rely on indirect evidence such as nests,tracks or burrows（地洞）.The first word"He"in paragraph 6 refers toA:Andrew Plumptre.B:Katy Payne.C:Anthony Chifu Nchanji.D:the writer of the article.
Why do researchers estimate elephant numbers in an area by counting dung piles?A Because elephants are difficult to catch.B Because it is not possible to count elephants from a plane.C Because it is not possible to keep track of elephants.D Because elephants are shy animals.
共用题干第二篇Don't Count on DungConservationists（自然保护主义者）may be miscalculating the numbers of the threatened animals such as elephants,say African and American researchers.The error occurs because of a flaw in the way they estimate animal numbers from the piles of dung （粪）the creatures leave behind.The mistake could lead researchers to think that there are twice as many elephants as there really are in some regions,according to Andrew Plumptre of the Wildlife Conservation Society(WCS)in New York.Biologist Katy Payne of Cornell University in Ithaca,New York,agrees.“We really need to know elephant numbers and the evidence that we have is quite indirect,"says Payne,who electronically tracks elephants.Counting elephants from planes is impossible in the vast rainforests of Central Africa.So researchers often estimate elephant numbers by counting dung piles in a given area.They also need to know the rate at which dung decays.Because it's extremely difficult to determine these rates,however,researchers counting elephants in one region tend to rely on standard decay rates established elsewhere.But researchers at the WCS have found that this decay rate varies from region to region depending on the climate and environment.Using the wrong values can lead the censusastray（离开正道）,says Plumptre.He and his colleague Anthony Chifu Nchanji studied decaying elephant dung in the forests of Cameroon.They found that the dung decayed between 55 and 65 per cent more slowly than the dung in the rainforests of neighbouring Gabon.If researchers use decay rates from Gabon to count elephants in Cameroon,they would probably find more elephants than are actually around.This could mean estimates in Cameroon are at least twice as high as those derived from decay rates calculated locally,says Plumptre."However accurate your dung densityestimate might be,the decay rate can severely affect the result.''Plumptre also says that the dung-pile census should be carried out over a region similar in size to an elephant's natural range.The usual technique of monitoring only small, protected areas distorts numbers because elephants move in and out of these regions,he says."If the elephant population increases within the protected area,you can not determine whether it is a real increase or whether it is due to elephants moving in because they are being poached（入侵偷猎）outside."Plumptre says that similar problems may also affect other animal census studies that rely on indirect evidence such as nests,tracks or burrows（地洞）.Piles of dung can't be relied upon when it comes to estimating elephant numbers becauseA:they are different in size.B:they scatter all over the region.C:they are different in decay rate.D:they are different in quality.
共用题干第二篇Don't Count on Dung（粪便）Conservationists（自然保护主义者）may be miscalculating the numbers of the threatened animals such as elephants,say African and American researchers. The error occurs because of a flaw in the way they estimate animal numbers from the piles of dung（粪）the creatures leave behind.The mistake could lead researchers to think that there are twice as many elephants as there really are in some regions according to Andrew Plumptre of the Wildlife Conservation Society(WCS)in New York.Biologist Katy Payne of Cornell University in Ithaca,New York,agrees,"We really need to know elephant numbers and the evidence that we have is quite indirect,"says Payne,who electronically tracks elephants.Counting elephants from planes is impossible in the vast rainforests of Central Africa. So researchers often estimate elephant numbers by counting dung piles in a given area. They also need to know the rate at which dung decays because it's extremely difficult to determine these rates. However,researchers counting elephants in one region tend to rely on standard decay rates established elsewhere.But researchers at the WCS have found that this decay rate varies from region to region depending on the climate and environment. "Using the wrong values can lead the census astray（离开正道）,"says Plumptre.He and his colleague Anthony Chifu Nchanji studied decaying elephant dung in the forests of Cameroon.They found that the dung decayed between 55 and 65 percent more slowly than the dung in the rainforests of neighbouring Gabon.If researchers use decay rates from Gabon to count elephants in Cameroon,they would probably find more elephants than are actually around.This could mean estimates in Cameroon are at least twice as high as those derived from decay rates calculated locally,says Plumptre"However accurate your dung density estimate might be,the decay rate can severely affect the result."Plumptre also says that the dung-pile census should be carried out over a region similar in size to an elephant's natural range.The usual technique of monitoring only small,protected areas distorts numbers because elephants move in and out of these regions,he says"If the elephant population increases within the protected area,you cannot determine whether it is a real increase or whether it is due to elephants moving in because they are being poached（入侵偷猎）outside."Plumptre says that similar problems may also affect other animal census studies that rely on indirect evidence such as nests,tracks or burrows（地洞）. Piles of dung can't be relied upon when it comes to estimating elephant numbers because______.A:they are different in sizeB:they scatter an over the regionC:they are different in decay rateD:they are different in quality
共用题干第二篇Don't Count on Dung（粪便）Conservationists（自然保护主义者）may be miscalculating the numbers of the threatened animals such as elephants,say African and American researchers. The error occurs because of a flaw in the way they estimate animal numbers from the piles of dung（粪）the creatures leave behind.The mistake could lead researchers to think that there are twice as many elephants as there really are in some regions according to Andrew Plumptre of the Wildlife Conservation Society(WCS)in New York.Biologist Katy Payne of Cornell University in Ithaca,New York,agrees,"We really need to know elephant numbers and the evidence that we have is quite indirect,"says Payne,who electronically tracks elephants.Counting elephants from planes is impossible in the vast rainforests of Central Africa. So researchers often estimate elephant numbers by counting dung piles in a given area. They also need to know the rate at which dung decays because it's extremely difficult to determine these rates. However,researchers counting elephants in one region tend to rely on standard decay rates established elsewhere.But researchers at the WCS have found that this decay rate varies from region to region depending on the climate and environment. "Using the wrong values can lead the census astray（离开正道）,"says Plumptre.He and his colleague Anthony Chifu Nchanji studied decaying elephant dung in the forests of Cameroon.They found that the dung decayed between 55 and 65 percent more slowly than the dung in the rainforests of neighbouring Gabon.If researchers use decay rates from Gabon to count elephants in Cameroon,they would probably find more elephants than are actually around.This could mean estimates in Cameroon are at least twice as high as those derived from decay rates calculated locally,says Plumptre"However accurate your dung density estimate might be,the decay rate can severely affect the result."Plumptre also says that the dung-pile census should be carried out over a region similar in size to an elephant's natural range.The usual technique of monitoring only small,protected areas distorts numbers because elephants move in and out of these regions,he says"If the elephant population increases within the protected area,you cannot determine whether it is a real increase or whether it is due to elephants moving in because they are being poached（入侵偷猎）outside."Plumptre says that similar problems may also affect other animal census studies that rely on indirect evidence such as nests,tracks or burrows（地洞）.According to Plumptre,the region over which a dung-pile census is carried out should be______.A:small enough B:well protectedC:carefully monitored D:large enough
共用题干第二篇Don't Count on Dung（粪便）Conservationists（自然保护主义者）may be miscalculating the numbers of the threatened animals such as elephants,say African and American researchers. The error occurs because of a flaw in the way they estimate animal numbers from the piles of dung（粪）the creatures leave behind.The mistake could lead researchers to think that there are twice as many elephants as there really are in some regions according to Andrew Plumptre of the Wildlife Conservation Society(WCS)in New York.Biologist Katy Payne of Cornell University in Ithaca,New York,agrees,"We really need to know elephant numbers and the evidence that we have is quite indirect,"says Payne,who electronically tracks elephants.Counting elephants from planes is impossible in the vast rainforests of Central Africa. So researchers often estimate elephant numbers by counting dung piles in a given area. They also need to know the rate at which dung decays because it's extremely difficult to determine these rates. However,researchers counting elephants in one region tend to rely on standard decay rates established elsewhere.But researchers at the WCS have found that this decay rate varies from region to region depending on the climate and environment. "Using the wrong values can lead the census astray（离开正道）,"says Plumptre.He and his colleague Anthony Chifu Nchanji studied decaying elephant dung in the forests of Cameroon.They found that the dung decayed between 55 and 65 percent more slowly than the dung in the rainforests of neighbouring Gabon.If researchers use decay rates from Gabon to count elephants in Cameroon,they would probably find more elephants than are actually around.This could mean estimates in Cameroon are at least twice as high as those derived from decay rates calculated locally,says Plumptre"However accurate your dung density estimate might be,the decay rate can severely affect the result."Plumptre also says that the dung-pile census should be carried out over a region similar in size to an elephant's natural range.The usual technique of monitoring only small,protected areas distorts numbers because elephants move in and out of these regions,he says"If the elephant population increases within the protected area,you cannot determine whether it is a real increase or whether it is due to elephants moving in because they are being poached（入侵偷猎）outside."Plumptre says that similar problems may also affect other animal census studies that rely on indirect evidence such as nests,tracks or burrows（地洞）.Why do researchers estimate elephant numbers in an area by counting dung piles?A:Because elephants are difficult to catch.B:Because it is not possible to count elephants from a plane.C:Because it is not possible to keep track of elephants.D:Because elephants are shy anitnals.
共用题干第二篇Don't Count on Dung（粪便）Conservationists（自然保护主义者）may be miscalculating the numbers of the threatened animals such as elephants,say African and American researchers. The error occurs because of a flaw in the way they estimate animal numbers from the piles of dung（粪）the creatures leave behind.The mistake could lead researchers to think that there are twice as many elephants as there really are in some regions according to Andrew Plumptre of the Wildlife Conservation Society(WCS)in New York.Biologist Katy Payne of Cornell University in Ithaca,New York,agrees,"We really need to know elephant numbers and the evidence that we have is quite indirect,"says Payne,who electronically tracks elephants.Counting elephants from planes is impossible in the vast rainforests of Central Africa. So researchers often estimate elephant numbers by counting dung piles in a given area. They also need to know the rate at which dung decays because it's extremely difficult to determine these rates. However,researchers counting elephants in one region tend to rely on standard decay rates established elsewhere.But researchers at the WCS have found that this decay rate varies from region to region depending on the climate and environment. "Using the wrong values can lead the census astray（离开正道）,"says Plumptre.He and his colleague Anthony Chifu Nchanji studied decaying elephant dung in the forests of Cameroon.They found that the dung decayed between 55 and 65 percent more slowly than the dung in the rainforests of neighbouring Gabon.If researchers use decay rates from Gabon to count elephants in Cameroon,they would probably find more elephants than are actually around.This could mean estimates in Cameroon are at least twice as high as those derived from decay rates calculated locally,says Plumptre"However accurate your dung density estimate might be,the decay rate can severely affect the result."Plumptre also says that the dung-pile census should be carried out over a region similar in size to an elephant's natural range.The usual technique of monitoring only small,protected areas distorts numbers because elephants move in and out of these regions,he says"If the elephant population increases within the protected area,you cannot determine whether it is a real increase or whether it is due to elephants moving in because they are being poached（入侵偷猎）outside."Plumptre says that similar problems may also affect other animal census studies that rely on indirect evidence such as nests,tracks or burrows（地洞）.The word"threatened"in the first sentence of the first paragraph could be best replaced by______.A:endangered B:frightenedC:killed D:angered
单选题At first why didn’t the writer want to climb down the rocks?AShe was afraid she would fall.BShe was too far away from pool.CShe thought the bees would follow her.DShe didn’t want her face to be unprotected.
单选题The speaker of the passage is of the opinion that ______.Aprotecting the farmland is more important than protecting wild animalBprotecting endangered species is more important than protecting the interests of the farmersCprotecting the farmland and the wild animals are equally importantDone can rely more on bees than mice to frighten beasts off the farm
单选题Some people start Buy Nothing Day because they think _____ .Apeople need more time to do other thingsBpeople buy too many gifts for ChristmasCpeople can hardly afford to buy a lot of giftsDpeople waste too much time going shopping
填空题The idea of a maintenance technician at Burt’s Bees turned out to be helpful and energy-efficient.____
单选题Trees become unhealthy if the gardener _____.Aallows too many branches to grow in the middleBdoes not protect them from windCforces them to grow too quicklyDdamages some of the small side branches
单选题What is an effective way of keeping the elephants away from farmland?APlacing hives full of bees on the farmland that elephants frequent.BPlacing empty bee hives on the farmland.CPlacing either occupied bee hives or empty ones on the farmland.DReleasing the bees in the face of an approaching elephants.