学历教育 - 英语考试
共用题干
The Impact of Antarctic Ozone Hole
The Antarctic ozone（臭氧）hole is changing weather patterns across the Southern Hemisphere （半球）,even affecting the tropics,scientists have concluded. The scientists______(51)the new study added the ozone hole into standard climate models to_______(52)how it might have affected winds and rains. They say rainfall has moved further south towards the pole and the effect has been_______(53)strong over Australia.
And of_______(54)interest was the southward of the Southern Hemisphere jet stream. These high一altitude winds are_______(55)to determining weather patterns,in both hemispheres. Much of the cold weather felt in the UK_______(56)the last couple of winters,for example,was caused by blocking of the Northern Hemisphere stream.
The team found that overall,the ozone hole has_______(57)in rainfall moving south along with the winds._______(58)there are regional differences,particularly concerning Australia. In terms of the average for that zone,the ozone hole_______(59)about a 10% change一but for Australia,it's about 35%.
Their modeling indicated that global warming_______(60)greenhouse gas emissions is also a factor in changing rainfall patterns.
Natural climate cycles are also thought to be important here,as different rainfall patterns were _______(61)in the era before ozone depletion（消耗）and late 20th Century warming.
Although the_______(62)international organization has significantly checked emissions of harmful substances,they_______(63)for decades in the atmosphere,and so their effects are still being felt.Earlier,and international organization forecast that even the Antarctic ozone hole一which is more severe than its_______(64)in the Northern Hemisphere一should be_______(65)by 2045—2060.
_________(52)
A:inspect
B:scan
C:investigate
D:supervise
查看答案
The Impact of Antarctic Ozone Hole
The Antarctic ozone（臭氧）hole is changing weather patterns across the Southern Hemisphere （半球）,even affecting the tropics,scientists have concluded. The scientists______(51)the new study added the ozone hole into standard climate models to_______(52)how it might have affected winds and rains. They say rainfall has moved further south towards the pole and the effect has been_______(53)strong over Australia.
And of_______(54)interest was the southward of the Southern Hemisphere jet stream. These high一altitude winds are_______(55)to determining weather patterns,in both hemispheres. Much of the cold weather felt in the UK_______(56)the last couple of winters,for example,was caused by blocking of the Northern Hemisphere stream.
The team found that overall,the ozone hole has_______(57)in rainfall moving south along with the winds._______(58)there are regional differences,particularly concerning Australia. In terms of the average for that zone,the ozone hole_______(59)about a 10% change一but for Australia,it's about 35%.
Their modeling indicated that global warming_______(60)greenhouse gas emissions is also a factor in changing rainfall patterns.
Natural climate cycles are also thought to be important here,as different rainfall patterns were _______(61)in the era before ozone depletion（消耗）and late 20th Century warming.
Although the_______(62)international organization has significantly checked emissions of harmful substances,they_______(63)for decades in the atmosphere,and so their effects are still being felt.Earlier,and international organization forecast that even the Antarctic ozone hole一which is more severe than its_______(64)in the Northern Hemisphere一should be_______(65)by 2045—2060.
_________(52)
A:inspect
B:scan
C:investigate
D:supervise
Charles Whecler's paintings often highlight the sharp edges and geometrical shapes of machines.
A:extend
B:emphasize
C:distort
D:soften
查看答案
A:extend
B:emphasize
C:distort
D:soften
共用题干
EcoDorm
Thoreau said education often made straight-cut ditches out of twisting small streams.But not at the EcoDorm,which houses 36 undergraduates and is the spiritual heart of Warren Willege,a liberal arts school of fewer than 1,000 students in Swannanoa,N.C.
In recent years,colleges like Warren Wilson took a leading role in the sustainability movement, which seeks to develop a durable human relationship with the environment.More than 600 US colleges and universities have signed up for a pledge to become carbon neutral.Ninety dorms are now LEED certified,the most widely accepted national standard for green design.The EcoDorm is one of only two student residences that have LEED's highest rating.
Two Warren Wilson students first proposed the dorm a decade ago.Undergraduates on the planning committee initially suggested that it be built with corncobs or straw. The design,by Asheville一based Samsel Architects, required compromises一as well as a number of creative solutions.The wood used for building the walls was harvested from campus trees that were suffering from a certain disease.The kitchen cabinets were made from recycled fence posts.Rainwater is collected into a disused railway tanker car and pumped back into the house to clean the low-flow toilets.Two toilets,which convert decaying organic matter to fertilizer,are also available on the second floor; students shovel（铲）in wood chips after they use them. The EcoDorm consumes nearly two-thirds less electricity than would a conventional building of the same size.
Margo Flood,the executive director of Warren Wilson's Environmental Leadership Center,says those who apply to live there"see an integration between their actions and their values".They pledge not to use hair dryers.Their music does not have its sound made louder electronically. The residents plant and harvest scores of fruits and vegetables in their garden.
The EcoDorm's residents speak of the comfort of finding a home where their values are shared. "I didn't have to worry about paper towels being wasted or feeling bad about drying my clothes out-side,"Jeremy Lekich,a senior who oversees the dorm's garden,says."Basically,it has made my life easier."
Paragraph 5________
A:The residents' integration between their actions and their values.
B:The comfort of EcoDorm.
C:How Ecodorm was built.
D:How rainwater is collected to clean toilets.
E:Colleges' leading role in sustainable development.
F:The EcoDorm's consumption.
查看答案
EcoDorm
Thoreau said education often made straight-cut ditches out of twisting small streams.But not at the EcoDorm,which houses 36 undergraduates and is the spiritual heart of Warren Willege,a liberal arts school of fewer than 1,000 students in Swannanoa,N.C.
In recent years,colleges like Warren Wilson took a leading role in the sustainability movement, which seeks to develop a durable human relationship with the environment.More than 600 US colleges and universities have signed up for a pledge to become carbon neutral.Ninety dorms are now LEED certified,the most widely accepted national standard for green design.The EcoDorm is one of only two student residences that have LEED's highest rating.
Two Warren Wilson students first proposed the dorm a decade ago.Undergraduates on the planning committee initially suggested that it be built with corncobs or straw. The design,by Asheville一based Samsel Architects, required compromises一as well as a number of creative solutions.The wood used for building the walls was harvested from campus trees that were suffering from a certain disease.The kitchen cabinets were made from recycled fence posts.Rainwater is collected into a disused railway tanker car and pumped back into the house to clean the low-flow toilets.Two toilets,which convert decaying organic matter to fertilizer,are also available on the second floor; students shovel（铲）in wood chips after they use them. The EcoDorm consumes nearly two-thirds less electricity than would a conventional building of the same size.
Margo Flood,the executive director of Warren Wilson's Environmental Leadership Center,says those who apply to live there"see an integration between their actions and their values".They pledge not to use hair dryers.Their music does not have its sound made louder electronically. The residents plant and harvest scores of fruits and vegetables in their garden.
The EcoDorm's residents speak of the comfort of finding a home where their values are shared. "I didn't have to worry about paper towels being wasted or feeling bad about drying my clothes out-side,"Jeremy Lekich,a senior who oversees the dorm's garden,says."Basically,it has made my life easier."
Paragraph 5________
A:The residents' integration between their actions and their values.
B:The comfort of EcoDorm.
C:How Ecodorm was built.
D:How rainwater is collected to clean toilets.
E:Colleges' leading role in sustainable development.
F:The EcoDorm's consumption.
共用题干
Animal's “Sixth Sense”
A tsunami（海啸）was triggered（引发）by an earthquake in the Indian Ocean in December, 2004.It killed tens of thousands of people in Asia and East Africa. Wild animals,1， seem to have escaped that terrible tsunami. This phenomenon adds weight to notions that they possess a“sixth sense” for2 ,experts said.
Sri Lankan wildlife officials have said the giant waves that killed over 24,000 people along the Indian Ocean island's coast clearly 3 wild beasts,with no dead animals found.
“No elephants are dead,not4a dead rabbit. I think animals can5 disaster.
They have a sixth sense. They know when things are happening,”H.D. Ratnayake,deputy director of Sri Lanka's Wildlife Department,said about one month after the tsunami attack. The6washed floodwaters up to 2 miles inland at Yala National Park in the ravaged（被 毁坏的）southeast, Sri Lanka's biggest wildlife7and home to hundreds of wild elephants and several leopards（豹）.
“There has been a lot of8 evidence about dogs barking or birds migrating before volcanic eruptions（火山爆发）or earthquakes. But it has not been proven ,” said Matthew van Lierop,an animal behavior 9 at Johannesburg Zoo.
“There have been no10studies because you can't really test it in a lab or field setting , ” he told Reuters. Other authorities concurred（同意）with this11.
“Wildlife seem to be able to pick up certain12 ,especially birds…there are many re- ports of birds detecting impending（迫近的）disasters , ” said Clive Walker , who has written several books on African wildlife.
Animals13 rely on the known senses such as smell or hearing to avoid danger such as predators（食肉动物）.
The notion of an animal “sixth sense”一or14other mythical power一is an enduring one which the evidence on Sri Lanka's ravaged coast is likely to add15.
8._________
A: experimental
B: apparent
C: scientific
D: chemical
查看答案
Animal's “Sixth Sense”
A tsunami（海啸）was triggered（引发）by an earthquake in the Indian Ocean in December, 2004.It killed tens of thousands of people in Asia and East Africa. Wild animals,1， seem to have escaped that terrible tsunami. This phenomenon adds weight to notions that they possess a“sixth sense” for2 ,experts said.
Sri Lankan wildlife officials have said the giant waves that killed over 24,000 people along the Indian Ocean island's coast clearly 3 wild beasts,with no dead animals found.
“No elephants are dead,not4a dead rabbit. I think animals can5 disaster.
They have a sixth sense. They know when things are happening,”H.D. Ratnayake,deputy director of Sri Lanka's Wildlife Department,said about one month after the tsunami attack. The6washed floodwaters up to 2 miles inland at Yala National Park in the ravaged（被 毁坏的）southeast, Sri Lanka's biggest wildlife7and home to hundreds of wild elephants and several leopards（豹）.
“There has been a lot of8 evidence about dogs barking or birds migrating before volcanic eruptions（火山爆发）or earthquakes. But it has not been proven ,” said Matthew van Lierop,an animal behavior 9 at Johannesburg Zoo.
“There have been no10studies because you can't really test it in a lab or field setting , ” he told Reuters. Other authorities concurred（同意）with this11.
“Wildlife seem to be able to pick up certain12 ,especially birds…there are many re- ports of birds detecting impending（迫近的）disasters , ” said Clive Walker , who has written several books on African wildlife.
Animals13 rely on the known senses such as smell or hearing to avoid danger such as predators（食肉动物）.
The notion of an animal “sixth sense”一or14other mythical power一is an enduring one which the evidence on Sri Lanka's ravaged coast is likely to add15.
8._________
A: experimental
B: apparent
C: scientific
D: chemical
共用题干
Microchip Research Center Created
A research center has been______(51)in this Far Eastern country to develop advanced microchip pro-duction technology.The center,which will start out with about US$14 million,will help the country develop its chip industry without always depending on imported technology.
The center will make use of its research skills and______(52)to develop new technology for ______(53)chip plants.The advent of the center will possibly free the country from the______(54)that it is always buying almost-outdated technologies from other countries,said the country's flagship chipmaker.______(55),chip plants in this country are in a passive situation because many foreign governments don't allowthem to______(56)the most advanced technologies,fearing they will be used for______(57) purposes.Moreover,the high licensing fees they have to pay to technology providers are also an important ______(58)for their decision of self-reliance.
As mainstream chip production technology______(59)from one generation to the next every three to five years,plants with new technology can make more powerful chips at lower costs,while plants with ______(60)equipment,which often cost billions of dollars to build,will be______(61)by the maker.
More than 10 chip plants are being built,each costing millions of US dollars.The majority of that money goes to overseas equipment______(62)and technology owners-mainly______(63)Japan and Singapore.
Should the new center play a major role in improving the situation in the industry,the country admits the US $14 million investment is still rather small.This country is developing______(64)technologies.Most of the investment will be spent on setting______(65)with technology and intellectual property owners.
59._________
A:transports
B:controls
C:shifts
D:turns
查看答案
Microchip Research Center Created
A research center has been______(51)in this Far Eastern country to develop advanced microchip pro-duction technology.The center,which will start out with about US$14 million,will help the country develop its chip industry without always depending on imported technology.
The center will make use of its research skills and______(52)to develop new technology for ______(53)chip plants.The advent of the center will possibly free the country from the______(54)that it is always buying almost-outdated technologies from other countries,said the country's flagship chipmaker.______(55),chip plants in this country are in a passive situation because many foreign governments don't allowthem to______(56)the most advanced technologies,fearing they will be used for______(57) purposes.Moreover,the high licensing fees they have to pay to technology providers are also an important ______(58)for their decision of self-reliance.
As mainstream chip production technology______(59)from one generation to the next every three to five years,plants with new technology can make more powerful chips at lower costs,while plants with ______(60)equipment,which often cost billions of dollars to build,will be______(61)by the maker.
More than 10 chip plants are being built,each costing millions of US dollars.The majority of that money goes to overseas equipment______(62)and technology owners-mainly______(63)Japan and Singapore.
Should the new center play a major role in improving the situation in the industry,the country admits the US $14 million investment is still rather small.This country is developing______(64)technologies.Most of the investment will be spent on setting______(65)with technology and intellectual property owners.
59._________
A:transports
B:controls
C:shifts
D:turns
共用题干
Forests for Cities
You are standing in a beautiful forest in Japan. The air is clean and smells like plants and
flowers. There are 175 different kinds of trees,and 60 kinds of birds live here.______(1)
You are downtown in the city of Nara,Japan,in Kasugayama Forest,the oldest urban forest in the world. It was started more than a thousand years ago,and today it's very popular with tourists and artists.
Cities around the world are working to protect their urban forests. Some urban forests are parks,and some are just streets with a lot of trees. But all urban forests have many good effects on the environment.______(2)They also stop the noise from heavy traffic. They even make the weather better because they make the air 3-5 degrees cooler,and they stop strong winds.
Urban forests also have many good effects on people. They make the city more beautiful. In a crowded area,they give people a place to relax and spend time in nature.______(3)
In some countries,people are starting new urban forests. In England,there are now 1.3 million trees in an urban forest called Thames Chase,east of London. It was started in 1990, and it has grown very fast.Walking and bicycle clubs use the forest,and there are programs for children and artists.______(4)
Some older cities don't have space for a big urban forest,but planting trees on the streets makes the city better. Scientists found that commuters（通勤人员）feel more relaxed when they can see trees. Trees are even good for business.______(5)In the future,urban forests will become even more important as our cities grow bigger. In the megacities（超大城市）of to-morrow,people will need more green space to live a comfortable life. Planting trees today will make our lives better in the future.
______(3)
A: People spend more time at shopping centers that have trees.
B: In hot countries,urban forests are cool places for walking and other healthy exercises.
C: But you are not in rural area.
D: Trees take pollution out of the air.
E: In 2033,it will have 5 million trees.
F: It has many kinds of birds in the country.
查看答案
Forests for Cities
You are standing in a beautiful forest in Japan. The air is clean and smells like plants and
flowers. There are 175 different kinds of trees,and 60 kinds of birds live here.______(1)
You are downtown in the city of Nara,Japan,in Kasugayama Forest,the oldest urban forest in the world. It was started more than a thousand years ago,and today it's very popular with tourists and artists.
Cities around the world are working to protect their urban forests. Some urban forests are parks,and some are just streets with a lot of trees. But all urban forests have many good effects on the environment.______(2)They also stop the noise from heavy traffic. They even make the weather better because they make the air 3-5 degrees cooler,and they stop strong winds.
Urban forests also have many good effects on people. They make the city more beautiful. In a crowded area,they give people a place to relax and spend time in nature.______(3)
In some countries,people are starting new urban forests. In England,there are now 1.3 million trees in an urban forest called Thames Chase,east of London. It was started in 1990, and it has grown very fast.Walking and bicycle clubs use the forest,and there are programs for children and artists.______(4)
Some older cities don't have space for a big urban forest,but planting trees on the streets makes the city better. Scientists found that commuters（通勤人员）feel more relaxed when they can see trees. Trees are even good for business.______(5)In the future,urban forests will become even more important as our cities grow bigger. In the megacities（超大城市）of to-morrow,people will need more green space to live a comfortable life. Planting trees today will make our lives better in the future.
______(3)
A: People spend more time at shopping centers that have trees.
B: In hot countries,urban forests are cool places for walking and other healthy exercises.
C: But you are not in rural area.
D: Trees take pollution out of the air.
E: In 2033,it will have 5 million trees.
F: It has many kinds of birds in the country.
共用题干
Read With Greater Speed
Do you have difficulty reading in class?If so,a special reading program that helps
match sounds with letters could speed up your brain.
At least one out of every five elementary school students in the U.S. has trouble
learnina to read .even when the students are good at other subjects.________(1)
Researchers from Yale University,U.S.,studied a group of children trom New YorK
and Connecticut State.As part of the study,37 struggling readers received special tutoring.
Every day,instructors worked with them on recognizing how written letters represent
units of sound called phonemes（音素）.________(2)
By the end of the school year,these children could read faster than before.They also
made fewer mistakes,and understood more of what they read than they coula earlier in the
year.
As part of their study,the researchers used a special machine to take action photos of
the students' brains.
________(3)This is the same part of the brain that becomes active when good
readers read.This activated brain area appears to include a structure that helps people
recognize familiar written words quickly.In lower level readers,this structure remains inactive.
A year later,the brain structure was still working hard in the students who had gone through
the special tutoring,and they continued to do well in reading tests.________(4)
However,some researchers still doubt the study.________(5)
________(5)
A:Many adults are interested in matching sounds with letters.
B:The students also practiced reading aloud and spelling.
C:The biggest challenge for many of these kids,scientists say,is matching sounds with letters.
D:Another group in the study who went through a more traditional reading program didn't show the same progress.
E:The pictures showed an increase in activity in the back of the brain on the left side.
F:They believe that reading without making any noise or linking words to sounds is more efficient.
查看答案
Read With Greater Speed
Do you have difficulty reading in class?If so,a special reading program that helps
match sounds with letters could speed up your brain.
At least one out of every five elementary school students in the U.S. has trouble
learnina to read .even when the students are good at other subjects.________(1)
Researchers from Yale University,U.S.,studied a group of children trom New YorK
and Connecticut State.As part of the study,37 struggling readers received special tutoring.
Every day,instructors worked with them on recognizing how written letters represent
units of sound called phonemes（音素）.________(2)
By the end of the school year,these children could read faster than before.They also
made fewer mistakes,and understood more of what they read than they coula earlier in the
year.
As part of their study,the researchers used a special machine to take action photos of
the students' brains.
________(3)This is the same part of the brain that becomes active when good
readers read.This activated brain area appears to include a structure that helps people
recognize familiar written words quickly.In lower level readers,this structure remains inactive.
A year later,the brain structure was still working hard in the students who had gone through
the special tutoring,and they continued to do well in reading tests.________(4)
However,some researchers still doubt the study.________(5)
________(5)
A:Many adults are interested in matching sounds with letters.
B:The students also practiced reading aloud and spelling.
C:The biggest challenge for many of these kids,scientists say,is matching sounds with letters.
D:Another group in the study who went through a more traditional reading program didn't show the same progress.
E:The pictures showed an increase in activity in the back of the brain on the left side.
F:They believe that reading without making any noise or linking words to sounds is more efficient.
共用题干
Price Planning
A price represents the value of goods or service for both the seller and the buyer. Price planning is the
systematic decision made by an organization after regarding all aspects of pricing.
The value of goods or service can involve both tangible and intangible marketing factors.An example of
a tangible marketing factor is the cost savings_(46).An example of an intangible marketin
factor is a consumer's pride in the ownership of a Lamborghini rather than another brand of automobile.To
make a deal,both the buyer and seller must feel that the price of goods or service provides an equitable
value.To the buyer,the payment of a price reduces purchasing power_________(47).To the seller,
receipt of a price is a source of revenue and an important determinant of sales and profit levels.
Many words are substitutes for the term price:admission fee,membership fee,rate,tuition,service charge,
donation,rent,salary,interest,retainer,and assessment.No matter what it is called,________(48):mone-
tary and non-monetary charges,discounts,handling and shipping fees,credit charges and other forms of inter-
est,and late-payment penalties. A non-price exchange would be selling a new iron for 10 books of trading
stamps or an airline offering tickets as payment for advertising space and time.Monetary and non-monetary ex-
change may be combined.This is common with automobiles,________(49).This combination allows a re-
duction in the monetary price.
From a broader perspective,price is the mechanism for allocating goods and services among potential
purchasers and for ensuring competition among sellers in an open market economy.If there is an excess of de-
mand over supply,prices are usually bid up by consumers.If there is an excess of supply over demand,
_________ (50).
_________(47)
A:a price contains all the connotation of other terms of purchase
B:obtained by the purchase of a new bottling machine by a soda manufacturer
C:where the consumer gives the seller money plus a trade-in
D:available for other items
E:prices are usually reduced by sellers
F: price means what one pays for what he wants
查看答案
Price Planning
A price represents the value of goods or service for both the seller and the buyer. Price planning is the
systematic decision made by an organization after regarding all aspects of pricing.
The value of goods or service can involve both tangible and intangible marketing factors.An example of
a tangible marketing factor is the cost savings_(46).An example of an intangible marketin
factor is a consumer's pride in the ownership of a Lamborghini rather than another brand of automobile.To
make a deal,both the buyer and seller must feel that the price of goods or service provides an equitable
value.To the buyer,the payment of a price reduces purchasing power_________(47).To the seller,
receipt of a price is a source of revenue and an important determinant of sales and profit levels.
Many words are substitutes for the term price:admission fee,membership fee,rate,tuition,service charge,
donation,rent,salary,interest,retainer,and assessment.No matter what it is called,________(48):mone-
tary and non-monetary charges,discounts,handling and shipping fees,credit charges and other forms of inter-
est,and late-payment penalties. A non-price exchange would be selling a new iron for 10 books of trading
stamps or an airline offering tickets as payment for advertising space and time.Monetary and non-monetary ex-
change may be combined.This is common with automobiles,________(49).This combination allows a re-
duction in the monetary price.
From a broader perspective,price is the mechanism for allocating goods and services among potential
purchasers and for ensuring competition among sellers in an open market economy.If there is an excess of de-
mand over supply,prices are usually bid up by consumers.If there is an excess of supply over demand,
_________ (50).
_________(47)
A:a price contains all the connotation of other terms of purchase
B:obtained by the purchase of a new bottling machine by a soda manufacturer
C:where the consumer gives the seller money plus a trade-in
D:available for other items
E:prices are usually reduced by sellers
F: price means what one pays for what he wants
He was kept in appalling conditions in prison.
A:necessary
B:terrible
C:critical
D:normal
查看答案
A:necessary
B:terrible
C:critical
D:normal
共用题干
第三篇
The Exploding Lakes of Cameroon
What comes to mind when you think of a lake?You probably imagine a pretty scene
with blue water,birds,and fish.For the people in the northwestern Cameroon,however,
the image is very different.For them,lakes may mean terrible disasters.In 1984,
poisonous gases exploded out of Lake Monoun and came down into the nearby villages,
killing thirty-seven people.Two years later,Lake Nyos erupted.A cloud of gases rolled
down the hills and into the valleys and killed 1,700 people.
Lake Nyos and Lake Monoun are crater（火山口）lakes. They were formed when
water collected in the craters of old volcanoes.The volcanoes under Lake Nyos and Lake
Monoun are not active anymore.However,poisonous gases from the center of the earth
continue to flow up through cracks in the bottom of the lake.This is normal in a crater lake.
In most crater lakes,these gases are released often because the water"turns over"
regularly.That is,the water from the bottom of the lake rises and mixes with the water at
the top,allowing the gases to escape slowly.
However,in Lakes Nyos and Monoun,there is no regular turning over.No one knows
the reason for this fact,but as a result,these lakes have more gases trapped at the bottom
than other crater lakes.In fact,scientists who have studied Lakes Nyos and Monoun have
found 16,000 times more gases.When a strong wind,cool weather,a storm,or a
landslide（滑坡）causes the water to turn over suddenly,the gases escape in a violent
explosion.
In the past,no one knew when the gases might explode,so there was no way for the
villagers to escape disaster. Now scientists from the United States,France,and
Cameroon have found a way to reduce the gas pressure at the bottom of Lake Nyos.They
stood a 672-foot plastic pipe in the middle of the lake,with one end of the pipe near the
bottom and the other end in the air. Near the top of the pipe,the team put several holes
that could be opened or closed by a computer.Now,when the gas pressure gets too high,
the holes are opened and some of the gas-filled water shoots up through the pipe into the air
like a fountain.With less pressure,a disastrous explosion is much less likely.However,
the scientists are not sure that one pipe will be enough to prevent explosions.They hope to
put in others soon and they plan to install a similar pipe and a computer system at Lake
Monoun as well.
To protect people nearby until all of the pipes are in place,the scientists have installed
early warning systems at both lakes.If the gas pressure rises to a dangerous level,
computers will set off loud sirens（警报）and bright lights to warn the people in the villages.
That way,they will have time to escape from the dangerous gases.
Lake Nyos and Lake Monoun explode because
A:the gases rise to the top and mix with air.
B:people from the villages turn over the water.
C:scientists have put in a computer system.
D:they have more gases trapped at the bottom than other crater lakes.
查看答案
第三篇
The Exploding Lakes of Cameroon
What comes to mind when you think of a lake?You probably imagine a pretty scene
with blue water,birds,and fish.For the people in the northwestern Cameroon,however,
the image is very different.For them,lakes may mean terrible disasters.In 1984,
poisonous gases exploded out of Lake Monoun and came down into the nearby villages,
killing thirty-seven people.Two years later,Lake Nyos erupted.A cloud of gases rolled
down the hills and into the valleys and killed 1,700 people.
Lake Nyos and Lake Monoun are crater（火山口）lakes. They were formed when
water collected in the craters of old volcanoes.The volcanoes under Lake Nyos and Lake
Monoun are not active anymore.However,poisonous gases from the center of the earth
continue to flow up through cracks in the bottom of the lake.This is normal in a crater lake.
In most crater lakes,these gases are released often because the water"turns over"
regularly.That is,the water from the bottom of the lake rises and mixes with the water at
the top,allowing the gases to escape slowly.
However,in Lakes Nyos and Monoun,there is no regular turning over.No one knows
the reason for this fact,but as a result,these lakes have more gases trapped at the bottom
than other crater lakes.In fact,scientists who have studied Lakes Nyos and Monoun have
found 16,000 times more gases.When a strong wind,cool weather,a storm,or a
landslide（滑坡）causes the water to turn over suddenly,the gases escape in a violent
explosion.
In the past,no one knew when the gases might explode,so there was no way for the
villagers to escape disaster. Now scientists from the United States,France,and
Cameroon have found a way to reduce the gas pressure at the bottom of Lake Nyos.They
stood a 672-foot plastic pipe in the middle of the lake,with one end of the pipe near the
bottom and the other end in the air. Near the top of the pipe,the team put several holes
that could be opened or closed by a computer.Now,when the gas pressure gets too high,
the holes are opened and some of the gas-filled water shoots up through the pipe into the air
like a fountain.With less pressure,a disastrous explosion is much less likely.However,
the scientists are not sure that one pipe will be enough to prevent explosions.They hope to
put in others soon and they plan to install a similar pipe and a computer system at Lake
Monoun as well.
To protect people nearby until all of the pipes are in place,the scientists have installed
early warning systems at both lakes.If the gas pressure rises to a dangerous level,
computers will set off loud sirens（警报）and bright lights to warn the people in the villages.
That way,they will have time to escape from the dangerous gases.
Lake Nyos and Lake Monoun explode because
A:the gases rise to the top and mix with air.
B:people from the villages turn over the water.
C:scientists have put in a computer system.
D:they have more gases trapped at the bottom than other crater lakes.