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第二篇
Are These Food Safe to Eat?
Traditionally,in plant breeding,there are crossing varieties of the same species in ways they could cross naturally.For example,disease-resistant varieties of wheat have been crossed with highyield wheat to combine these properties.This type of natural gene exchange is safe and fairly predictable.
Genetic engineering(GE)makes it possible to exchange genes between unrelated species that cannot exchange genes with each other in a natural way.GE can involve the exchange of genes be-tween vastly different species一e.g. putting scorpion toxin genes into maize or fish antifreeze genes into tomatoes.It is possible that a scorpion toxin gene,even when it is in maize DNA,will still get the organism to produce scorpion toxin一but what other effects may it have in this alien environment? We have already realized this problem一adding human growth hormone genes to pigs certainly makes them grow一but it also gives them arthritis and makes them cross-eyed,which was entirely out of expectation.
It won't be difficult to find out,for example,that the gene for human intelligence will not have the same effect if it is inserted into cabbage DNA as it had in human DNA一but what side-effect would it have?In other words,is genetically modified(GM)food safe to eat?The answer is that no-body knows because long-term tests have not been carried out.
Those companies who want a GM product approved in the UK or USA are required to provide regulatory bodies with results of their own safety tests.Monsanto's soya beans were apparently fed to fish for 10 weeks before being approved.There was no requirement for independent testing,for longterm testing,for testing on humans or testing for specific dangers to children or allergic people.
The present opinion of the British Government is that"There is no evidence of long-term dangers from GM foods."In the US,the American Food and Drug Administration is now being prosecuted for covering up research that suggested possible risks from GM foods.
Which type of natural gene exchange is safe and fairly predictable?
A:Adding human growth hormone genes to pigs.
B:Natural gene exchange in traditional plant breeding.
C:Inserting fish antifreeze genes into tomatoes.
D:Putting scorpion toxin genes into maize.
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共用题干
Europa's Watery Underworld
Europa,one of Jupiter's 63 known moons,looks bright and icy on the surface.But appearances can be
deceiving:Miles within its cracked,frigid shell,Europa probably hides giant pools of liquid water. Where
scientists find liquid water,they hope to find life as well.
Since we can't go diving into Europa's depths just yet,scientists instead have to investigate the moon's
surface for clues to what lies beneath.In a new study,scientists investigated one group of strange ice patterns
on Europa and concluded that the formations mark the top of an underground pool that holds as much water
as the U.S.Great Lakes.
Pictures of Europa,which is slightly smaller than Earth's moon,clearly show a tangled,icy mishmash
of lines and cracks known as"chaos terrains".These chaotic places cover more than half of Europa. For
more than 10 years,scientists have wondered what causes the formations.The new study suggests that they
arise from the mixing of vast underground stores of liquid water with icy material near the surface.
For scientists who suspect that Europa also may be hiding life beneath its icy surface,the news about
the new lake is exciting.
"It would be great if these lakes harbored life,"Britney Schmidt,a planetary scientist who worked on
the study,told Science News."But even if they didn't,they say that Europa is doing something interesting
and active right now."
Schmidt,a scientist at the University of Texas at Austin,and her colleagues wanted to know how chaos
terrains form.Since they couldn't rocket to Europa to see for themselves,they searched for similar forma-
tions here on Earth.They studied collapsed ice shelves in Antarctica and icy caps on volcanoes in Iceland.
Those features on Earth formed when liquid water mixed with ice.The scientists now suspect something
similar might be happening on Europa:that as water and ice of different temperatures mingle and shift,the
surface fractures.This would explain the jumbled ice sculptures.
"Fracturing catastrophically disrupts the ice in the same way that it causes ice shelves to collapse on
Earth,"Schmidt told Science News.She and her team found that the process could be causing chaos terrains
to form quickly on Europa.
The new study suggests that on this moon,elements such as oxygen from the surface blend with the
deep bodies of water. That mixture may create an environment that supports life.
Europa is the most recently discovered one among Jupiter's moons.
A:Right
B:Wrong
C:Not mentioned
Europa's Watery Underworld
Europa,one of Jupiter's 63 known moons,looks bright and icy on the surface.But appearances can be
deceiving:Miles within its cracked,frigid shell,Europa probably hides giant pools of liquid water. Where
scientists find liquid water,they hope to find life as well.
Since we can't go diving into Europa's depths just yet,scientists instead have to investigate the moon's
surface for clues to what lies beneath.In a new study,scientists investigated one group of strange ice patterns
on Europa and concluded that the formations mark the top of an underground pool that holds as much water
as the U.S.Great Lakes.
Pictures of Europa,which is slightly smaller than Earth's moon,clearly show a tangled,icy mishmash
of lines and cracks known as"chaos terrains".These chaotic places cover more than half of Europa. For
more than 10 years,scientists have wondered what causes the formations.The new study suggests that they
arise from the mixing of vast underground stores of liquid water with icy material near the surface.
For scientists who suspect that Europa also may be hiding life beneath its icy surface,the news about
the new lake is exciting.
"It would be great if these lakes harbored life,"Britney Schmidt,a planetary scientist who worked on
the study,told Science News."But even if they didn't,they say that Europa is doing something interesting
and active right now."
Schmidt,a scientist at the University of Texas at Austin,and her colleagues wanted to know how chaos
terrains form.Since they couldn't rocket to Europa to see for themselves,they searched for similar forma-
tions here on Earth.They studied collapsed ice shelves in Antarctica and icy caps on volcanoes in Iceland.
Those features on Earth formed when liquid water mixed with ice.The scientists now suspect something
similar might be happening on Europa:that as water and ice of different temperatures mingle and shift,the
surface fractures.This would explain the jumbled ice sculptures.
"Fracturing catastrophically disrupts the ice in the same way that it causes ice shelves to collapse on
Earth,"Schmidt told Science News.She and her team found that the process could be causing chaos terrains
to form quickly on Europa.
The new study suggests that on this moon,elements such as oxygen from the surface blend with the
deep bodies of water. That mixture may create an environment that supports life.
Europa is the most recently discovered one among Jupiter's moons.
A:Right
B:Wrong
C:Not mentioned
共用题干
第二篇
Students Learn Better with Touchscreen Desks
Observe the criticisms of nearly any major public education system in the world,and a few of the many
complaints are more or less universal.Technology moves faster than the education system.Teachers must
teach at the pace of the slowest student rather than the fastest. And一particularly in the United States一
school children as a group don't care much for,or excel（擅长）at,mathemnatics. So it's heartening to learn
that a new kind of"classroom of the future"shows promise at easing some of these problems,starting with
that fundamental piece of classroom furniture:the desk.
A UK study involving roughly 400 students,mostly aged 8一10 years,and a new generation of
multis-touch,multi-user,computerized desktop surfaces is showing that over the last three years the technology
has appreciably boosted students'math skills compared with peers learning the same material via the con-
ventional paper-and-pencil method.How?Through collaboration,mostly,as well as by giving teachers better
tools by which to micromanage individual students who need some extra instruction while allowing the rest of
the class to continue moving forward.
Traditional instruction still shows respectable efficacy（效力）at increasing students'fluency in mathe-
matics,essentially through memorization and practice一dull,repetitive practice.But the researchers have con-
cluded that these new touchscreen desks boost both fluency and flexibility一the critical thinking skills that al-
low students to solve complex problems not simply through knowing formulas and devices,but by being able
to figure out what the real problem is and the most effective means of stripping it down and solving it.
One reason for this,the researchers say,is the multi-touch aspect of the technology.Students working in
the next-gen classroom can work together at the same tabletop,each of them contributing and engaging with
the problem as part of a group.Known as SynergyNet,the software uses computer vision systems that see in
the infrared（红外线的）spectrum to distinguish between different touches on different parts of the surface,
allowing students to access and use tools on the screen,move objects and visual aids around on their desk-
tops,and otherwise physically interact with the numbers and information on their screens.By using these
screens collaboratively,the researchers say,the students are to some extent teaching themselves as those with
a stronger grasp on difficult concepts pull other students forward along with them.
How does the new tech work to improve students'mathematical learning?
A:It helps fast learners to learn faster.
B:It enables them to work together.
C:It makes teachers'instruction unnecessary.
D:It allows the whole class to learn at the same pace.
第二篇
Students Learn Better with Touchscreen Desks
Observe the criticisms of nearly any major public education system in the world,and a few of the many
complaints are more or less universal.Technology moves faster than the education system.Teachers must
teach at the pace of the slowest student rather than the fastest. And一particularly in the United States一
school children as a group don't care much for,or excel（擅长）at,mathemnatics. So it's heartening to learn
that a new kind of"classroom of the future"shows promise at easing some of these problems,starting with
that fundamental piece of classroom furniture:the desk.
A UK study involving roughly 400 students,mostly aged 8一10 years,and a new generation of
multis-touch,multi-user,computerized desktop surfaces is showing that over the last three years the technology
has appreciably boosted students'math skills compared with peers learning the same material via the con-
ventional paper-and-pencil method.How?Through collaboration,mostly,as well as by giving teachers better
tools by which to micromanage individual students who need some extra instruction while allowing the rest of
the class to continue moving forward.
Traditional instruction still shows respectable efficacy（效力）at increasing students'fluency in mathe-
matics,essentially through memorization and practice一dull,repetitive practice.But the researchers have con-
cluded that these new touchscreen desks boost both fluency and flexibility一the critical thinking skills that al-
low students to solve complex problems not simply through knowing formulas and devices,but by being able
to figure out what the real problem is and the most effective means of stripping it down and solving it.
One reason for this,the researchers say,is the multi-touch aspect of the technology.Students working in
the next-gen classroom can work together at the same tabletop,each of them contributing and engaging with
the problem as part of a group.Known as SynergyNet,the software uses computer vision systems that see in
the infrared（红外线的）spectrum to distinguish between different touches on different parts of the surface,
allowing students to access and use tools on the screen,move objects and visual aids around on their desk-
tops,and otherwise physically interact with the numbers and information on their screens.By using these
screens collaboratively,the researchers say,the students are to some extent teaching themselves as those with
a stronger grasp on difficult concepts pull other students forward along with them.
How does the new tech work to improve students'mathematical learning?
A:It helps fast learners to learn faster.
B:It enables them to work together.
C:It makes teachers'instruction unnecessary.
D:It allows the whole class to learn at the same pace.
共用题干
第一篇
What's NASDAQ?
NASDAQ is a familiar but strange name for people.We often learn its news via different kinds of media,though quite a lot of people can not tell what exactly it means.
NASDAQ,short for the National Association of Securities Dealers Automated Quotations system,is one of the largest market in the world for stocks trading. The number of companies in NASDAQ is more than that of the other stock exchange in America,including the New York Stock Exchange(NYSE)and the American Stock Exchange(AMEX).
Most of the companies listed on NASDAQ are smaller than most of those on the NYSE and AMEX.NASDAQ has become recognized as the home of new technology companies,especially computer and computer-related businesses.Trading on NASDAQ is initiated by stock brokers acting on behalf of their clients.The brokers negotiate with market makers who concentrate on trading specific stocks to reach a price for the stock.
Different from other stock exchange,NASDAQ has no central location where trading takes place.Instead,its market makers can be found all over the country and make trades by telephone and via the Internet. Since brokers and market makers trade stocks directly instead of on the floor of a stock exchange,NASDAQ is called an over-the-counter market. The term over-the-counter refers to the direct nature of the trading,as in a store where goods are handed over a counter.
Since its foundation in 1971,the NASDAQ Stock Market has been the innovator. As the world's first electronic stock market,NASDAQ long ago set a precedent for technological trading innovation that is unrivaled.Now poised to become the world's first truly global market,the NASDAQ Stock Market is the market of choice for business industry leaders worldwide.By providing an efficient environment for raising capital NASDAQ has helped thousands of companies achieve their desired growth and successfully make the leap into public ownership.
What does the passage mainly tell us?
A:The history of NASDAQ.
B:The difference between NASDAQ and other stock exchanges.
C:How NASDAQ is managed.
D:The general information about NASDAQ.
第一篇
What's NASDAQ?
NASDAQ is a familiar but strange name for people.We often learn its news via different kinds of media,though quite a lot of people can not tell what exactly it means.
NASDAQ,short for the National Association of Securities Dealers Automated Quotations system,is one of the largest market in the world for stocks trading. The number of companies in NASDAQ is more than that of the other stock exchange in America,including the New York Stock Exchange(NYSE)and the American Stock Exchange(AMEX).
Most of the companies listed on NASDAQ are smaller than most of those on the NYSE and AMEX.NASDAQ has become recognized as the home of new technology companies,especially computer and computer-related businesses.Trading on NASDAQ is initiated by stock brokers acting on behalf of their clients.The brokers negotiate with market makers who concentrate on trading specific stocks to reach a price for the stock.
Different from other stock exchange,NASDAQ has no central location where trading takes place.Instead,its market makers can be found all over the country and make trades by telephone and via the Internet. Since brokers and market makers trade stocks directly instead of on the floor of a stock exchange,NASDAQ is called an over-the-counter market. The term over-the-counter refers to the direct nature of the trading,as in a store where goods are handed over a counter.
Since its foundation in 1971,the NASDAQ Stock Market has been the innovator. As the world's first electronic stock market,NASDAQ long ago set a precedent for technological trading innovation that is unrivaled.Now poised to become the world's first truly global market,the NASDAQ Stock Market is the market of choice for business industry leaders worldwide.By providing an efficient environment for raising capital NASDAQ has helped thousands of companies achieve their desired growth and successfully make the leap into public ownership.
What does the passage mainly tell us?
A:The history of NASDAQ.
B:The difference between NASDAQ and other stock exchanges.
C:How NASDAQ is managed.
D:The general information about NASDAQ.
共用题干
第二篇
Students Learn Better with Touchscreen Desks
Observe the criticisms of nearly any major public education system in the world,and a few of the many
complaints are more or less universal.Technology moves faster than the education system.Teachers must
teach at the pace of the slowest student rather than the fastest. And一particularly in the United States一
school children as a group don't care much for,or excel（擅长）at,mathemnatics. So it's heartening to learn
that a new kind of"classroom of the future"shows promise at easing some of these problems,starting with
that fundamental piece of classroom furniture:the desk.
A UK study involving roughly 400 students,mostly aged 8一10 years,and a new generation of
multis-touch,multi-user,computerized desktop surfaces is showing that over the last three years the technology
has appreciably boosted students'math skills compared with peers learning the same material via the con-
ventional paper-and-pencil method.How?Through collaboration,mostly,as well as by giving teachers better
tools by which to micromanage individual students who need some extra instruction while allowing the rest of
the class to continue moving forward.
Traditional instruction still shows respectable efficacy（效力）at increasing students'fluency in mathe-
matics,essentially through memorization and practice一dull,repetitive practice.But the researchers have con-
cluded that these new touchscreen desks boost both fluency and flexibility一the critical thinking skills that al-
low students to solve complex problems not simply through knowing formulas and devices,but by being able
to figure out what the real problem is and the most effective means of stripping it down and solving it.
One reason for this,the researchers say,is the multi-touch aspect of the technology.Students working in
the next-gen classroom can work together at the same tabletop,each of them contributing and engaging with
the problem as part of a group.Known as SynergyNet,the software uses computer vision systems that see in
the infrared（红外线的）spectrum to distinguish between different touches on different parts of the surface,
allowing students to access and use tools on the screen,move objects and visual aids around on their desk-
tops,and otherwise physically interact with the numbers and information on their screens.By using these
screens collaboratively,the researchers say,the students are to some extent teaching themselves as those with
a stronger grasp on difficult concepts pull other students forward along with them.
What happens when students are using the desktop of the new tech?
A:Every student has an individual tabletop.
B:The multi-touch function stimulates students.
C:The software installed automatically identifies different users.
D:Students use different tools to interact with each other.
第二篇
Students Learn Better with Touchscreen Desks
Observe the criticisms of nearly any major public education system in the world,and a few of the many
complaints are more or less universal.Technology moves faster than the education system.Teachers must
teach at the pace of the slowest student rather than the fastest. And一particularly in the United States一
school children as a group don't care much for,or excel（擅长）at,mathemnatics. So it's heartening to learn
that a new kind of"classroom of the future"shows promise at easing some of these problems,starting with
that fundamental piece of classroom furniture:the desk.
A UK study involving roughly 400 students,mostly aged 8一10 years,and a new generation of
multis-touch,multi-user,computerized desktop surfaces is showing that over the last three years the technology
has appreciably boosted students'math skills compared with peers learning the same material via the con-
ventional paper-and-pencil method.How?Through collaboration,mostly,as well as by giving teachers better
tools by which to micromanage individual students who need some extra instruction while allowing the rest of
the class to continue moving forward.
Traditional instruction still shows respectable efficacy（效力）at increasing students'fluency in mathe-
matics,essentially through memorization and practice一dull,repetitive practice.But the researchers have con-
cluded that these new touchscreen desks boost both fluency and flexibility一the critical thinking skills that al-
low students to solve complex problems not simply through knowing formulas and devices,but by being able
to figure out what the real problem is and the most effective means of stripping it down and solving it.
One reason for this,the researchers say,is the multi-touch aspect of the technology.Students working in
the next-gen classroom can work together at the same tabletop,each of them contributing and engaging with
the problem as part of a group.Known as SynergyNet,the software uses computer vision systems that see in
the infrared（红外线的）spectrum to distinguish between different touches on different parts of the surface,
allowing students to access and use tools on the screen,move objects and visual aids around on their desk-
tops,and otherwise physically interact with the numbers and information on their screens.By using these
screens collaboratively,the researchers say,the students are to some extent teaching themselves as those with
a stronger grasp on difficult concepts pull other students forward along with them.
What happens when students are using the desktop of the new tech?
A:Every student has an individual tabletop.
B:The multi-touch function stimulates students.
C:The software installed automatically identifies different users.
D:Students use different tools to interact with each other.
共用题干
Sharks Perform a Service for Earth's Waters
It is hard to get people to think of sharks as anything but a deadly enemy.They are thought to ______(51)people frequently .But these fish perform a______(52)service for earth's waters and for human beings .Yet business and sport fishing are threatening their______(53).Some sharks are at______(54)of disappearing from earth.
Warm weather may influence both fish and shark activity.Many fish swim near coastal areas ______(55)their warm waters. Experts say sharks may follow the fish into the same areas, ______(56)people also swim.In fact,most sharks do not purposely charge at or bite humans.
They are thought to mistake a person______(57)a sea animal,such as a seal or sea lion.That is why people should not swim in the ocean when the sun goes down or comes up .Those are the ______(58)when sharks are looking for food.Experts also say that bright colors and shiny jewelry may cause sharks to attack.
A shark has an extremely good sense of smell.It can find small amounts of substances in water,such as blood,body liquids and______(59)produced by animals.These powerful ______(60)help sharks find their food.Sharks eat fish,any______(61)sharks,and plants that live in the ocean.
Medical researchers want to learn more about the shark's body defense and immune systems ______(62)disease.Researchers know that sharks______(63)quickly from injuries.They study the shark in hopes of finding a way to fight human disease.
Sharks are important for the world's______(64).They eat injured and diseased fish. Their hunting activities mean that the numbers of other fish in ocean waters do not become too ______(65).This protects the plants and other forms of life that exist in the oceans.
58._________
A:. times
B: places
C: seas
D: oceans
Sharks Perform a Service for Earth's Waters
It is hard to get people to think of sharks as anything but a deadly enemy.They are thought to ______(51)people frequently .But these fish perform a______(52)service for earth's waters and for human beings .Yet business and sport fishing are threatening their______(53).Some sharks are at______(54)of disappearing from earth.
Warm weather may influence both fish and shark activity.Many fish swim near coastal areas ______(55)their warm waters. Experts say sharks may follow the fish into the same areas, ______(56)people also swim.In fact,most sharks do not purposely charge at or bite humans.
They are thought to mistake a person______(57)a sea animal,such as a seal or sea lion.That is why people should not swim in the ocean when the sun goes down or comes up .Those are the ______(58)when sharks are looking for food.Experts also say that bright colors and shiny jewelry may cause sharks to attack.
A shark has an extremely good sense of smell.It can find small amounts of substances in water,such as blood,body liquids and______(59)produced by animals.These powerful ______(60)help sharks find their food.Sharks eat fish,any______(61)sharks,and plants that live in the ocean.
Medical researchers want to learn more about the shark's body defense and immune systems ______(62)disease.Researchers know that sharks______(63)quickly from injuries.They study the shark in hopes of finding a way to fight human disease.
Sharks are important for the world's______(64).They eat injured and diseased fish. Their hunting activities mean that the numbers of other fish in ocean waters do not become too ______(65).This protects the plants and other forms of life that exist in the oceans.
58._________
A:. times
B: places
C: seas
D: oceans