搜题
题目
The chemical is deadly to rats but safe to cattle.
A:useful
B:fatal
C:good
D:hateful
提示：未搜索到的试题可在搜索页快速提交，您可在会员中心"提交的题"快速查看答案。
答案
查看答案
搜题
相关试题
共用题干
第二篇
Sleep Lets Brain File Memories
To sleep.Perchance to file?Findings published online this week by the proceedings of the National Academy of Sciences further support the theory that the brain organizes and stows memories formed during the day while the rest of the body is catching zzz's.
Gyorgy Buzsaki of Rutgers University and his colleagues analyzed the brain waves of sleeping rats and mice. Specifically,they examined the electrical activity emanating（散发）from the somatosensory（耳、目、口等以外的）neocortex（新大脑皮层）(an area that processes sensory information) and the hippocampus（海马）,which is a center for learning and memory. The scientists found that oscillations in brain waves from the two regions appear to be intertwined.So-called sleep spindles (bursts of activity from the neocortex)were followed tens of milliseconds later by beats in the hippocampus known as ripples.The team posits that this interplay between the two brain regions is a key step in memory consolidation.
A second study,also published online this week by the proceedings of the National Academy of Sciences,links age-associated memory decline to high glucose levels.
Previous research had shown that individuals with diabetes（糖尿病，多尿症）suffer from increased memory problems.In the new work,Antonio Convit of New York University School of Medicine and his collaborators studied 30 people whose average age was 69 to investigate whether sugar levels,which tend to increase with age,affect memory in healthy people as well.The scientists administered recall tests, brain scans（细看，审视，浏览，扫描）and glucose tolerance tests, which measure how quickly sugar is absorbed from the blood by the body's tissues.Subjects with the poorest memory recollection,the team discovered,also displayed the poorest glucose tolerance.In addition,their brain scans showed more hippocampus shrinkage than those of subjects better able to absorb blood sugar.
" Our study suggests that this impairment（损害、损伤）may contribute to the memory deficits （赤字、不足额）that occur as people age."Convit says."And it raises the intriguing possibility that improving glucose tolerance could reverse some age-associated problems in cognition."Exercise and weight control can help keep glucose levels in check（阻止、制止）,so there may be one more reason to go to the gym.
In what way is memory related to hippocampus shrinkage?
A:There is no relation between memory and hippocampus shrinkage.
B:The more hippocampus shrinks,the poorer one's memory.
C:The more hippocampus shrinks,the better one's memory.
D:The less hippocampus shrinks,the poorer one's memory.
第二篇
Sleep Lets Brain File Memories
To sleep.Perchance to file?Findings published online this week by the proceedings of the National Academy of Sciences further support the theory that the brain organizes and stows memories formed during the day while the rest of the body is catching zzz's.
Gyorgy Buzsaki of Rutgers University and his colleagues analyzed the brain waves of sleeping rats and mice. Specifically,they examined the electrical activity emanating（散发）from the somatosensory（耳、目、口等以外的）neocortex（新大脑皮层）(an area that processes sensory information) and the hippocampus（海马）,which is a center for learning and memory. The scientists found that oscillations in brain waves from the two regions appear to be intertwined.So-called sleep spindles (bursts of activity from the neocortex)were followed tens of milliseconds later by beats in the hippocampus known as ripples.The team posits that this interplay between the two brain regions is a key step in memory consolidation.
A second study,also published online this week by the proceedings of the National Academy of Sciences,links age-associated memory decline to high glucose levels.
Previous research had shown that individuals with diabetes（糖尿病，多尿症）suffer from increased memory problems.In the new work,Antonio Convit of New York University School of Medicine and his collaborators studied 30 people whose average age was 69 to investigate whether sugar levels,which tend to increase with age,affect memory in healthy people as well.The scientists administered recall tests, brain scans（细看，审视，浏览，扫描）and glucose tolerance tests, which measure how quickly sugar is absorbed from the blood by the body's tissues.Subjects with the poorest memory recollection,the team discovered,also displayed the poorest glucose tolerance.In addition,their brain scans showed more hippocampus shrinkage than those of subjects better able to absorb blood sugar.
" Our study suggests that this impairment（损害、损伤）may contribute to the memory deficits （赤字、不足额）that occur as people age."Convit says."And it raises the intriguing possibility that improving glucose tolerance could reverse some age-associated problems in cognition."Exercise and weight control can help keep glucose levels in check（阻止、制止）,so there may be one more reason to go to the gym.
In what way is memory related to hippocampus shrinkage?
A:There is no relation between memory and hippocampus shrinkage.
B:The more hippocampus shrinks,the poorer one's memory.
C:The more hippocampus shrinks,the better one's memory.
D:The less hippocampus shrinks,the poorer one's memory.
共用题干
Computer Plug-in
1.Life on the Internet can be enriched if you don't restrict yourself to just written words and still pictures.Even if you are a newcomer to the Internet world,you've probably heard about multi-media on-line一listening to radio,watching animations and videos,even playing in three-dimensional space.Sound and movement make information come alive.
2.In order to experience that,some special pieces of software called plug-ins are necessary. The term"plug-in"refers to a small,add-on piece of software which extends the capabilities of your web browser,like Netscape Navigator or Microsoft Explorer,turning your computer into a radio or TV.
3.When you open a web page with a file requiring a plug-in which you don't have.you will usually receive a message asking if you want to get it by downloading it and installing it into your computer. Most of the time,the installation will be automatic.
4.Occasionally,you come across a downloaded file which needs to be decompressed or unzipped before installation.Once installed,plug-ins run automatically,without you having to do anything.
5.Many multimedia controls still need to be obtained from the developer but are installed automatically.
6.Shockwave is a typical example of it. All you need to do is go to the Macromedia site and click on the link to install the ActiveX control.The rest happens automatically.The next time you go to a"Shocked"website,the Shockwave control loads and plays the movie.
7.Most plug-ins and controls can be downloaded for free on the Internet,although not all will work with every system.Some of them,for instance,only work with Windows 95.
Paragraph 2_______
A:Life online can be colorful.
B:How plug-ins are installed.
C:Plug-ins should not be absent if you want to enjoy the Internet.
D:How Shockwave is installed and used.
E:No money is charged for the use of plug-ins.
F: The developer's permission is needed before you install a plug-in.
Computer Plug-in
1.Life on the Internet can be enriched if you don't restrict yourself to just written words and still pictures.Even if you are a newcomer to the Internet world,you've probably heard about multi-media on-line一listening to radio,watching animations and videos,even playing in three-dimensional space.Sound and movement make information come alive.
2.In order to experience that,some special pieces of software called plug-ins are necessary. The term"plug-in"refers to a small,add-on piece of software which extends the capabilities of your web browser,like Netscape Navigator or Microsoft Explorer,turning your computer into a radio or TV.
3.When you open a web page with a file requiring a plug-in which you don't have.you will usually receive a message asking if you want to get it by downloading it and installing it into your computer. Most of the time,the installation will be automatic.
4.Occasionally,you come across a downloaded file which needs to be decompressed or unzipped before installation.Once installed,plug-ins run automatically,without you having to do anything.
5.Many multimedia controls still need to be obtained from the developer but are installed automatically.
6.Shockwave is a typical example of it. All you need to do is go to the Macromedia site and click on the link to install the ActiveX control.The rest happens automatically.The next time you go to a"Shocked"website,the Shockwave control loads and plays the movie.
7.Most plug-ins and controls can be downloaded for free on the Internet,although not all will work with every system.Some of them,for instance,only work with Windows 95.
Paragraph 2_______
A:Life online can be colorful.
B:How plug-ins are installed.
C:Plug-ins should not be absent if you want to enjoy the Internet.
D:How Shockwave is installed and used.
E:No money is charged for the use of plug-ins.
F: The developer's permission is needed before you install a plug-in.
共用题干
Mother Nature Shows Her Strength
Tornadoes（龙卷风）and heavy thunderstorms moved across the Great Lakes and into Trumbull County
on Saturday evening.The storms were dramatic and dangerous.
George Snyder was driving the fire truck down Route 88 when he first noticed that a funnel（漏斗状的）
cloud was behind him."I stopped the truck and watched the funnel cloud.It was about 100 feet off the
ground and I saw it go up and down for a while.It was moving toward Bradley Road and then suddenly it
disappeared,"Snyder said.
Snyder only saw one of the funnel clouds that passed through northeastern Ohio on Saturday.In
Trumbull County,a tornado turned trees onto their sides.Some trees fell onto houses and cars.Other trees fell
onto telephone and electrical wires as thev went down.
Amanda Symcheck was having a party when the storm began."I knew something was wrong,"she said.
"I saw the sky go green and pink.Then it sounded like a train rushing toward the house.I started crying and
told everyone to go to the basement for protection."
The tornado caused a lot of damage to cars and houses in the area. It will take a long time and much
money to repair everything.There was also serious water damage from the thunderstorms.The heavy rains and
high wind caused the power to go out in many homes.
The storms caused serious flooding in areas near the river. More than four inches of rain fell in parts of
Trumbull County.The river was so high that the water ran into streets and houses.Many streets had to be
closed to cars and trucks because of the high water. This made it difficult for fire trucks,police cars,and
other rescue vehicles to help people who were in trouble.
Many people who live near the river had to leave their homes for their own safety.Some people reported
five feet of water in their homes.Local and state officials opened emergency shelters for the people who were
evacuated（撤走）.The Red Cross served meals to them.
"This was a really intense storm,"said Snyder,"People were afraid.Mother Nature can be fierce.We
were lucky this time.No one was killed."
Amanda Symcheck was having a party in the basement when the storm began.
A:Right
B:Wrong
C:Not mentioned
Mother Nature Shows Her Strength
Tornadoes（龙卷风）and heavy thunderstorms moved across the Great Lakes and into Trumbull County
on Saturday evening.The storms were dramatic and dangerous.
George Snyder was driving the fire truck down Route 88 when he first noticed that a funnel（漏斗状的）
cloud was behind him."I stopped the truck and watched the funnel cloud.It was about 100 feet off the
ground and I saw it go up and down for a while.It was moving toward Bradley Road and then suddenly it
disappeared,"Snyder said.
Snyder only saw one of the funnel clouds that passed through northeastern Ohio on Saturday.In
Trumbull County,a tornado turned trees onto their sides.Some trees fell onto houses and cars.Other trees fell
onto telephone and electrical wires as thev went down.
Amanda Symcheck was having a party when the storm began."I knew something was wrong,"she said.
"I saw the sky go green and pink.Then it sounded like a train rushing toward the house.I started crying and
told everyone to go to the basement for protection."
The tornado caused a lot of damage to cars and houses in the area. It will take a long time and much
money to repair everything.There was also serious water damage from the thunderstorms.The heavy rains and
high wind caused the power to go out in many homes.
The storms caused serious flooding in areas near the river. More than four inches of rain fell in parts of
Trumbull County.The river was so high that the water ran into streets and houses.Many streets had to be
closed to cars and trucks because of the high water. This made it difficult for fire trucks,police cars,and
other rescue vehicles to help people who were in trouble.
Many people who live near the river had to leave their homes for their own safety.Some people reported
five feet of water in their homes.Local and state officials opened emergency shelters for the people who were
evacuated（撤走）.The Red Cross served meals to them.
"This was a really intense storm,"said Snyder,"People were afraid.Mother Nature can be fierce.We
were lucky this time.No one was killed."
Amanda Symcheck was having a party in the basement when the storm began.
A:Right
B:Wrong
C:Not mentioned
It is postulated that a cure for the disease will have been found by the year 2020.
A:challenged
B:assumed
C:deducted
D:decreed
A:challenged
B:assumed
C:deducted
D:decreed
共用题干
第一篇
Plant Gas
Scientists have been studying natural sources of methane（甲烷，沼气）for decades but hadn't regarded plants as a producer, notes Frank Keppler, a geochemist（地球化学家）at the Max Planck Institute for Nuclear Physics in Heldelberg,Germany. Now Keppler and his colleagues find that plants,from grasses to trees,may also be sources of the greenhouse gas.This is really surprising, because most scientists assumed that methane production requires an oxygen-free environment.
Previously,researchers had thought that it was impossible for plants to make significant amounts of the gas. They had assumed that microbes（微生物）need to be in environments without oxygen to produce methane.Methane is a greenhouse gas, like carbon dioxide.Gases such as methane and carbon dioxide trap heat in Earth's atmosphere and contribute to global warming.
In its experiments, Keppler's team used sealed chambers（室，房间；腔）that contained the same concentration of oxygen that Earth's atmosphere has.They measured the amounts of methane that were released by both living plants and dried plant material,such as fallen leaves.
With the dried plants,the researchers took measurement at temperatures ranging from 30 degrees Celsius to 70 degrees C.At 30 degrees C.,they found,a gram of dried plant material released up to 3 nanograms（微克）of methane per hour(One nanogram is a millionth of a gram). With every 10-degree rise in temperature,the amount of methane released each hour roughly doubled.
Living plants growing at their normal temperatures released as much as 370 nanograms of methane per gram of plant tissue per hour. Methane emissions tripled when living and dead plant was exposed to sunlight.
Because there was plenty of oxygen available,it's unlikely that the types of bacteria(bacterium的复数，细菌）that normally make methane were involved. Experiments on plants that were grown in water rather than soil also resulted in methane emissions.That's another strong sign that the gas came from the plants and not soil microbes.
The new finding is an"interesting observation,"says Jennifer Y. King,a biogeochemist（生物地球化学家）at the University of Minnesota in St. Paul. Because some types of soil microbes consume methane,they may prevent plant-produced methane from reaching the atmosphere.Field tests will be needed to assess the plant's influence,she notes.
Which of the following about methane is not mentioned in the passage?
A:Plants growing in soil release methane.
B:Plants growing in water release methane.
C:Soil microbes consume methane.
D:Microbes in plants produce methane.
第一篇
Plant Gas
Scientists have been studying natural sources of methane（甲烷，沼气）for decades but hadn't regarded plants as a producer, notes Frank Keppler, a geochemist（地球化学家）at the Max Planck Institute for Nuclear Physics in Heldelberg,Germany. Now Keppler and his colleagues find that plants,from grasses to trees,may also be sources of the greenhouse gas.This is really surprising, because most scientists assumed that methane production requires an oxygen-free environment.
Previously,researchers had thought that it was impossible for plants to make significant amounts of the gas. They had assumed that microbes（微生物）need to be in environments without oxygen to produce methane.Methane is a greenhouse gas, like carbon dioxide.Gases such as methane and carbon dioxide trap heat in Earth's atmosphere and contribute to global warming.
In its experiments, Keppler's team used sealed chambers（室，房间；腔）that contained the same concentration of oxygen that Earth's atmosphere has.They measured the amounts of methane that were released by both living plants and dried plant material,such as fallen leaves.
With the dried plants,the researchers took measurement at temperatures ranging from 30 degrees Celsius to 70 degrees C.At 30 degrees C.,they found,a gram of dried plant material released up to 3 nanograms（微克）of methane per hour(One nanogram is a millionth of a gram). With every 10-degree rise in temperature,the amount of methane released each hour roughly doubled.
Living plants growing at their normal temperatures released as much as 370 nanograms of methane per gram of plant tissue per hour. Methane emissions tripled when living and dead plant was exposed to sunlight.
Because there was plenty of oxygen available,it's unlikely that the types of bacteria(bacterium的复数，细菌）that normally make methane were involved. Experiments on plants that were grown in water rather than soil also resulted in methane emissions.That's another strong sign that the gas came from the plants and not soil microbes.
The new finding is an"interesting observation,"says Jennifer Y. King,a biogeochemist（生物地球化学家）at the University of Minnesota in St. Paul. Because some types of soil microbes consume methane,they may prevent plant-produced methane from reaching the atmosphere.Field tests will be needed to assess the plant's influence,she notes.
Which of the following about methane is not mentioned in the passage?
A:Plants growing in soil release methane.
B:Plants growing in water release methane.
C:Soil microbes consume methane.
D:Microbes in plants produce methane.