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We are aware of the 【potential】 problems.
A. possible B. global C. ongoing D. central
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Ants Have Big Impact on Environment as“Ecosystem Engineers”
Research by the University of Exeter has revealed that ants have a big impact on their local environment as a result of their activity as“ecosystem engineers”and predators. The study,published in the Journal of Animal Ecology,found that ants have two distinct effects on their local environment.
Firstly,through moving of soil by nest building activity and by collecting food they af-fect the level of nutrients in the soil. This can indirectly impact the local populations of many animal groups,from decomposers to species much higher up the food chain.
Secondly,they prey on a wide range of other animals,including larger prey which can be attacked by vast numbers of ant workers.
Dirk Sanders,an author of the study from the university's Centre for Ecology and Con-servation,said:“Ants are very effective predators which thrive in huge numbers. They're al-so very territorial and very aggressive,defending their resources and territory against other predators. All of this means they have a strong influence on their surrounding area.”
“In this research,we studied for the first time how big this impact is and the subtleties of it. What we found is that despite being predators,their presence can also lead to an increase in density and diversity of other animal groups. They genuinely play a key role in the local environment,having a big influence on the grassland food web,”Sanders said.
The study,carried out in Germany,studied the impact of the presence of different combinations and densities of black garden ants and common red ants,both species which can be found across Europe,including in the UK.It found that a low density of ants in an area increased the diversity and density of other animals in the local area,particularly the density of herbivores and decomposers. At higher densities ants had no or the opposite effect,showing that predation is counteracting the positive influence.
Dr Frank van Veen,another author on the study,said:“What we find is that the impact of ants on soil nutrient levels has a positive effect on animal groups at low levels,but as the number of ants increases,their predatory impacts have the bigger effect一thereby counteracting the positive influence via ecosystem engineering.”
Ants are important components of ecosystems not only because they constitute a great part of the animal biomass but also because they act as ecosystem engineers. Ant biodiversity is incredibly high and these organisms are highly responsive to human impact,which obviously reduces its richness. However,it is not clear how such disturbance damages the maintenance of ant services to the ecosystem. Ants are important in below ground processes through the alteration of the physical and chemical environment and through their effects on plants,microorganisms,and other soil organisms.
As predators,ants______.
A:prey on small as well as large animals
B: collect nutritious food from the soil
C: collect food as decomposers
D: prey on species much higher up the food chain
Ants Have Big Impact on Environment as“Ecosystem Engineers”
Research by the University of Exeter has revealed that ants have a big impact on their local environment as a result of their activity as“ecosystem engineers”and predators. The study,published in the Journal of Animal Ecology,found that ants have two distinct effects on their local environment.
Firstly,through moving of soil by nest building activity and by collecting food they af-fect the level of nutrients in the soil. This can indirectly impact the local populations of many animal groups,from decomposers to species much higher up the food chain.
Secondly,they prey on a wide range of other animals,including larger prey which can be attacked by vast numbers of ant workers.
Dirk Sanders,an author of the study from the university's Centre for Ecology and Con-servation,said:“Ants are very effective predators which thrive in huge numbers. They're al-so very territorial and very aggressive,defending their resources and territory against other predators. All of this means they have a strong influence on their surrounding area.”
“In this research,we studied for the first time how big this impact is and the subtleties of it. What we found is that despite being predators,their presence can also lead to an increase in density and diversity of other animal groups. They genuinely play a key role in the local environment,having a big influence on the grassland food web,”Sanders said.
The study,carried out in Germany,studied the impact of the presence of different combinations and densities of black garden ants and common red ants,both species which can be found across Europe,including in the UK.It found that a low density of ants in an area increased the diversity and density of other animals in the local area,particularly the density of herbivores and decomposers. At higher densities ants had no or the opposite effect,showing that predation is counteracting the positive influence.
Dr Frank van Veen,another author on the study,said:“What we find is that the impact of ants on soil nutrient levels has a positive effect on animal groups at low levels,but as the number of ants increases,their predatory impacts have the bigger effect一thereby counteracting the positive influence via ecosystem engineering.”
Ants are important components of ecosystems not only because they constitute a great part of the animal biomass but also because they act as ecosystem engineers. Ant biodiversity is incredibly high and these organisms are highly responsive to human impact,which obviously reduces its richness. However,it is not clear how such disturbance damages the maintenance of ant services to the ecosystem. Ants are important in below ground processes through the alteration of the physical and chemical environment and through their effects on plants,microorganisms,and other soil organisms.
As predators,ants______.
A:prey on small as well as large animals
B: collect nutritious food from the soil
C: collect food as decomposers
D: prey on species much higher up the food chain
共用题干
The World's Best-Selling Medicine
Since ancient times,people all over the world have used willow to stop pain. The willow tree contains salicylic acid（水杨酸）.This stops pain, but there is one problem. Salicylic acid also hurts the stomach. In 1853,a French scientist made a mixture from willow that did not hurt the stomach.
However,his mixture was difficult to make,and he did not try to produce or sell it.
In 1897,in Germany,Felix Hoffmann also made a mixture with salicylic acid. He tried it himself first and then gave it to his father because his father was old and in a lot of pain.
His father's pain went away,and the mixture did not hurt his stomach.
Hoffmann worked for Bayer,a German company. He showed his new drug to his manager,who tested the drug and found that it worked well.Bayer decided to make the drug.
They called it aspirin and put the Bayer name on every pill.
Aspirin was an immediate success. Almost everyone has pain of some kind,so aspirin answered a true need. Aspirin was cheap,easy to take,and effective. It also lowered fevers.
Aspirin was a wonder drug.
At first,Bayer sold the drug through doctors,who then sold it to their patients. In 1915,the company started to sell aspirin in drugstores.In the United States,Bayer had a patent（专利权）on the drug. Other companies could make similar products and sell them in other countries,but only bayer could make and sell aspirin in the United States.In time,Bayer could no longer own the name aspirin in the United States. Other companies could make it there,too.However,Bayer aspirin was the most well known,and for many years,it was the market leader.
By the 1950s,new painkillers were on the market. Aspirin was no longer the only way to treat pain and reduce fever. Bayer and other companies looked for other drugs to make.However,in the l970s they got a surprise. Doctors noticed that patients who were taking aspirin had fewer heart attacks than other people. A British researcher named John Vane found the reason aspirin helped to prevent heart attacks.In 1982,he won the Nobel prize for his research. Doctors started to tell some of their patients to take aspirin every day to prevent heart attacks.It has made life better for the many people who take it. It has also made a lot of mon-ey for companies like Bayer that produce and sell it!
Why was Felix Hoffmann looking for a painkiller?
A: His company told him to do that.
B: His father was in pain.
C: He wanted to make a lot of money.
D: He suffered from headache.
The World's Best-Selling Medicine
Since ancient times,people all over the world have used willow to stop pain. The willow tree contains salicylic acid（水杨酸）.This stops pain, but there is one problem. Salicylic acid also hurts the stomach. In 1853,a French scientist made a mixture from willow that did not hurt the stomach.
However,his mixture was difficult to make,and he did not try to produce or sell it.
In 1897,in Germany,Felix Hoffmann also made a mixture with salicylic acid. He tried it himself first and then gave it to his father because his father was old and in a lot of pain.
His father's pain went away,and the mixture did not hurt his stomach.
Hoffmann worked for Bayer,a German company. He showed his new drug to his manager,who tested the drug and found that it worked well.Bayer decided to make the drug.
They called it aspirin and put the Bayer name on every pill.
Aspirin was an immediate success. Almost everyone has pain of some kind,so aspirin answered a true need. Aspirin was cheap,easy to take,and effective. It also lowered fevers.
Aspirin was a wonder drug.
At first,Bayer sold the drug through doctors,who then sold it to their patients. In 1915,the company started to sell aspirin in drugstores.In the United States,Bayer had a patent（专利权）on the drug. Other companies could make similar products and sell them in other countries,but only bayer could make and sell aspirin in the United States.In time,Bayer could no longer own the name aspirin in the United States. Other companies could make it there,too.However,Bayer aspirin was the most well known,and for many years,it was the market leader.
By the 1950s,new painkillers were on the market. Aspirin was no longer the only way to treat pain and reduce fever. Bayer and other companies looked for other drugs to make.However,in the l970s they got a surprise. Doctors noticed that patients who were taking aspirin had fewer heart attacks than other people. A British researcher named John Vane found the reason aspirin helped to prevent heart attacks.In 1982,he won the Nobel prize for his research. Doctors started to tell some of their patients to take aspirin every day to prevent heart attacks.It has made life better for the many people who take it. It has also made a lot of mon-ey for companies like Bayer that produce and sell it!
Why was Felix Hoffmann looking for a painkiller?
A: His company told him to do that.
B: His father was in pain.
C: He wanted to make a lot of money.
D: He suffered from headache.
共用题干
Common-cold Sense
You can't beat it,but you don't have to join it.Maybe it got the name"common cold"because it's more common in winter.The fact is,though,being cold doesn't have anything to do with getting one.Colds are caused by the spread of rhinoviruses,and,at least so far,medical science is better at telling you how to avoid getting one than how to get rid of one.
Children are the most common way cold viruses are spread to adults,because they have more colds than adults-an average of about eight per year.Why do kids seem so much more easily to get colds than their parents?Simple.They haven't had the opportunity to become immune to many cold viruses.
There are more than 150 different cold viruses,and you never have the same one twice.being infected by one makes you immune to it-but only it.
Colds are usually spread by direct contact,not sneezing or coughing.From another person's hand to your hand and then to your nose or eyes is the most common route.The highest concentration of cold viruses anywhere is found under the thumbnails of a boy,although the viruses can survive for hours on skin or other smooth surfaces.
Hygiene is your best defense.Wash your hands frequently,preferably with a disinfectant soap,especially when children in your household have colds.
But even careful hygiene won't ward off every cold.So,what works when a coughing,sneezing, runny nose strikes?
The old prescription of two aspirins,lots of water,and bed rest is a good place to start.But you'll also find some of the folk remedies worth trying.Hot mixtures of sugar(or honey),lemon,and water have real benefits.
According to the essay,you may have a cold because.
A:the weather is too cold
B:the spread of rhinoviruses gets people infected
C:another person's coughing passes the cold to you
D:you wash your hands too often
Common-cold Sense
You can't beat it,but you don't have to join it.Maybe it got the name"common cold"because it's more common in winter.The fact is,though,being cold doesn't have anything to do with getting one.Colds are caused by the spread of rhinoviruses,and,at least so far,medical science is better at telling you how to avoid getting one than how to get rid of one.
Children are the most common way cold viruses are spread to adults,because they have more colds than adults-an average of about eight per year.Why do kids seem so much more easily to get colds than their parents?Simple.They haven't had the opportunity to become immune to many cold viruses.
There are more than 150 different cold viruses,and you never have the same one twice.being infected by one makes you immune to it-but only it.
Colds are usually spread by direct contact,not sneezing or coughing.From another person's hand to your hand and then to your nose or eyes is the most common route.The highest concentration of cold viruses anywhere is found under the thumbnails of a boy,although the viruses can survive for hours on skin or other smooth surfaces.
Hygiene is your best defense.Wash your hands frequently,preferably with a disinfectant soap,especially when children in your household have colds.
But even careful hygiene won't ward off every cold.So,what works when a coughing,sneezing, runny nose strikes?
The old prescription of two aspirins,lots of water,and bed rest is a good place to start.But you'll also find some of the folk remedies worth trying.Hot mixtures of sugar(or honey),lemon,and water have real benefits.
According to the essay,you may have a cold because.
A:the weather is too cold
B:the spread of rhinoviruses gets people infected
C:another person's coughing passes the cold to you
D:you wash your hands too often
共用题干
Trying to Find a Partner
One of the most striking findings of a recent poii in the UK is that of the people interviewed, one in two believes that it is becoming more difficult to meet someone to start a family with.
Why are many finding it increasingly difficult to start and sustain intimate relationships?
Does modern life really make it harder to , fall in love?Or are we making it harder for ourselves?
It is certainly the case today that contemporary couples benefit in different ways from relationships.Women no longer rely upon partners for economic security or status.A man doesn't expect his spouse to be in sole charge of running his household and raising his children.
But perhaps the knowledge that we can live perfectly well without a partnership means that it takes much more to persuade people to abandon their independence.
In theory,finding a partner should be much simpler these days.Only a few generations ago, your choice of soulmate（心上人）was constrained by geography , social convention and family tradition .Although it was never explicit,many marriages were essentially arranged.
Now those barriers have been broken down.You can approach a builder or a brain surgeon in any bar in any city on any given evening. When the world is your oyster（牡砺）,you surely have a better chance of finding a pearl.
But it seems that the old conventions have been replaced by an even tighter constraint:the tyranny of choice.
The expectations of partners are inflated to an unmanageable degree:good looks,impressive salary,kind to grandmother,and right socks.There is no room for error in the first impression.
We think that a relationship can be perfect. If it isn't,it is disposable.We work to protect ourselves against future heartache and don't put in the hard emotional labor needed to build a strong relationship.Of course,this is complicated by realities.The cost of housing and child-rearing creates pressure to have a stable income and career before a life partnership.
What does the recent poil show?
A: It is getting more difficult for a woman to find her husband.
B: It is getting increasingly difficult to start a family.
C: It is getting more difficult for a man to find his wife.
D: It is getting increasingly difficult to develop an intimate relationship with your spouse.
Trying to Find a Partner
One of the most striking findings of a recent poii in the UK is that of the people interviewed, one in two believes that it is becoming more difficult to meet someone to start a family with.
Why are many finding it increasingly difficult to start and sustain intimate relationships?
Does modern life really make it harder to , fall in love?Or are we making it harder for ourselves?
It is certainly the case today that contemporary couples benefit in different ways from relationships.Women no longer rely upon partners for economic security or status.A man doesn't expect his spouse to be in sole charge of running his household and raising his children.
But perhaps the knowledge that we can live perfectly well without a partnership means that it takes much more to persuade people to abandon their independence.
In theory,finding a partner should be much simpler these days.Only a few generations ago, your choice of soulmate（心上人）was constrained by geography , social convention and family tradition .Although it was never explicit,many marriages were essentially arranged.
Now those barriers have been broken down.You can approach a builder or a brain surgeon in any bar in any city on any given evening. When the world is your oyster（牡砺）,you surely have a better chance of finding a pearl.
But it seems that the old conventions have been replaced by an even tighter constraint:the tyranny of choice.
The expectations of partners are inflated to an unmanageable degree:good looks,impressive salary,kind to grandmother,and right socks.There is no room for error in the first impression.
We think that a relationship can be perfect. If it isn't,it is disposable.We work to protect ourselves against future heartache and don't put in the hard emotional labor needed to build a strong relationship.Of course,this is complicated by realities.The cost of housing and child-rearing creates pressure to have a stable income and career before a life partnership.
What does the recent poil show?
A: It is getting more difficult for a woman to find her husband.
B: It is getting increasingly difficult to start a family.
C: It is getting more difficult for a man to find his wife.
D: It is getting increasingly difficult to develop an intimate relationship with your spouse.
共用题干
Exercise
Whether or not exercise adds___1___the length of life,it is common experience that a certain___2___of regular exercise improves the health and contributes a feeling of wellbeing.
Furthermore,exercise___3___involves play and recreation,and relieves nervous tension and mental fatigue in so doing,is not only pleasant but beneficial. How much and what kind of exercise one should___4___merits careful consideration. The growing child and the normal young man and young woman thrill with the exhilaration of strenuous sports.They fatigue to the___5___of exhaustion but recover promptly with a period of rest. But not so with___6___of middle age and beyond. For them moderation is___7___vital importance. Just how much exercise a person of a given age can safely take is a question___8___to answer. Individual variability is___9___ great to permit of generalization.
A game of tennis may be perfectly safe for one person of forty but folly for another. The safe limit for exercise___10___ on the condition of the heart,the condition of the muscles,the type of exercise,and the regularity with which it is taken.Two general suggestions,however,will___11___ as sound advice for anyone.The first is that the condition of the heart and general health should be___12___ periodically by careful, thorough physical examinations. The___13___is that exercise should be kept below the point of physical exhaustion.
What type of exercise one should___14___depends upon one's physical condition. Young people can safely enjoy vigorous competitive sports,but most older persons do better to limit themselves to less strenuous activities. Walking,swimming,skating are among the sports that one can enjoy and safely participate___15___throughout life. Regularity is important if one is to get the most enjoyment and benefit out of exercise.
8._________
A: easy
B: hard
C: impossible
D: unnecessary
Exercise
Whether or not exercise adds___1___the length of life,it is common experience that a certain___2___of regular exercise improves the health and contributes a feeling of wellbeing.
Furthermore,exercise___3___involves play and recreation,and relieves nervous tension and mental fatigue in so doing,is not only pleasant but beneficial. How much and what kind of exercise one should___4___merits careful consideration. The growing child and the normal young man and young woman thrill with the exhilaration of strenuous sports.They fatigue to the___5___of exhaustion but recover promptly with a period of rest. But not so with___6___of middle age and beyond. For them moderation is___7___vital importance. Just how much exercise a person of a given age can safely take is a question___8___to answer. Individual variability is___9___ great to permit of generalization.
A game of tennis may be perfectly safe for one person of forty but folly for another. The safe limit for exercise___10___ on the condition of the heart,the condition of the muscles,the type of exercise,and the regularity with which it is taken.Two general suggestions,however,will___11___ as sound advice for anyone.The first is that the condition of the heart and general health should be___12___ periodically by careful, thorough physical examinations. The___13___is that exercise should be kept below the point of physical exhaustion.
What type of exercise one should___14___depends upon one's physical condition. Young people can safely enjoy vigorous competitive sports,but most older persons do better to limit themselves to less strenuous activities. Walking,swimming,skating are among the sports that one can enjoy and safely participate___15___throughout life. Regularity is important if one is to get the most enjoyment and benefit out of exercise.
8._________
A: easy
B: hard
C: impossible
D: unnecessary
