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US scientists say they have poured cold water on the theory that washing hands with hot water kills more germs (细菌) than unheated water. The small study of 20 people found using water at 15C (59F) left hands as clean as water heated to 38C (100F).
National Health Service (NHS) recommends that people wash their hands in either cold or warm water. In this study, scientists at Rutgers University-New Brunswick wanted to find out if popular assumptions about the benefits of warm or hot water and official guidance on hot water —given to the food industry in the US - held true. They asked 20 people to wash their hands 20 times each with water that was 15C (59F), 26C (79F) or 38 degrees (100F). Volunteers were also asked to experiment with varying amounts of soap. Before they started the tests, their hands were covered in harmless bugs. Researchers say there was no difference in the amount of bugs removed as the temperature of the water or the amount of soap changed.
Prof Donald Schaffner said: “People need to feel comfortable when they are washing their hands but as far as effectiveness goes, this study shows us that the temperature of the water used did not matter.”
However, the researchers accept their study is small and say more extensive work is needed to determine the best ways to remove harmful bacteria.
In the UK, NHS experts say people can use cold or hot water to wash their hands. They say hands should be washed for at least 20 seconds and stress the importance of using enough soap to cover the whole surface of the hands. Their guidance focuses on rubbing hands together in various .ways to make sure each surface of each hand is clean.
1.What does the underlined phrase “poured cold water” in Paragraph 1 probably mean?
A. Proved. B. Created.
C. Contradicted. D. Accepted.
2.After they washed their hands with either hot or cold water, .
A. volunteers nearly had the same amount of germ removed
B. volunteers all talked about American food industry
C. volunteers still had much germ on their hands
D. volunteers all didn’t feel very comfortable
3.How do researchers feel about their study?
A. It is popular. B. It is incomplete.
C. It is convincing. D. It is abstract.
4.Which of the following is the best title for the text?
A. Using Cold Water Instead of Hot Water
B. How to Use Cold Water to Wash Hands
C. It Is Better to Wash Hands in Cold Water
D. Washing Hands in Cold Water as Good as in Hot Water
高三英语阅读理解困难题查看答案及解析
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US scientists say they have poured cold water on the theory that washing hands with hot water kills more germs (细菌) than unheated water. The small study of 20 people found using water at 15℃ (59F) left hands as clean as water heated to 38℃ (100F).
National Health Service (NHS) recommends that people wash their hands in either cold or warm water. In this study, scientists at Rutgers University-New Brunswick wanted to find out if popular assumptions about the benefits of warm or hot water and official guidance on hot water — given to the food industry in the US — held true. They asked 20 people to wash their hands 20 times each with water that was 15℃ (59F), 26℃ (79F) or 38 degrees (100F). Volunteers were also asked to experiment with varying amounts of soap. Before they started the tests, their hands were covered in harmless bugs. Researchers say there was no difference in the amount of bugs removed as the temperature of the water or the amount of soap changed.
Prof Donald Schaffner said: “People need to feel comfortable when they are washing their hands but as far as effectiveness goes, this study shows us that the temperature of the water used did not matter.”
However, the researchers accept their study is small and say more extensive work is needed to determine the best ways to remove harmful bacteria.
In the UK, NHS experts say people can use cold or hot water to wash their hands. They say hands should be washed for at least 20 seconds and stress the importance of using enough soap to cover the whole surface of the hands. Their guidance focuses on rubbing hands together in various ways to make sure each surface of each hand is clean.
1.What does the underlined phrase “poured cold water” in Paragraph 1 probably mean?
A. Proved. B. Contradicted.
C. Created. D. Accepted.
2.After they washed their hands with either hot or cold water, ________.
A. volunteers all didn’t feel very comfortable
B. volunteers all talked about American food industry
C. volunteers still had much germ on their hands
D. volunteers nearly had the same amount of germ removed
3.How do the researchers feel about their study?
A. It is popular. B. It is convincing.
C. It is incomplete. D. It is abstract.
4.Which of the following is the best title for the text?
A. Using Cold Water Instead of Hot Water
B. How to Use Cold Water to Wash Hands
C. It Is Better to Wash Hands in Cold Water
D. Washing Hands in Cold Water as Good as Hot
高三英语阅读理解中等难度题查看答案及解析
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Scientists say they now have proof to support the old-fashioned advice that it’s best to sleep on a problem．They say sleep strengthens the memory and helps the brain organize the masses of information we receive each day．
The lead researcher Bob Stickgold at the Harvard Medical School said, “Sleep helps us draw rules from our experiences．It’s like knowing the difference between dogs and cats even if it’s hard to explain．”
The US research team studied how well students remembered connections between words and symbols, reports New Scientist．They compared how the students performed if they had had a sleep between seeing the words and having the test, and if they had not slept．They found that people were better able to remember lists of related words after a night’s sleep than after the same time spent awake during the day．They also found it easier to remember themes that the words had in common．But they forgot around one in four more themes if they had been awake．
Prof．John Groeger, of Survey University’s Sleep Research Centre, said, “People have been trying for years to find out what the purpose of sleep is, as we know that only certain parts of it have a restorative （促使康复的）value．”
“We form and store huge numbers of experiences in the head every day, and sleep seems to be the way the brain deals with them all．”
1.The phrase “to sleep on a problem” in Paragraph 1 most likely means “________”．
A．to pay full attention to a problem
B．to wait until the next day for a decision
C．to sleep to forget a problem
D．to have difficulty in sleeping
2.In the study by the US research team, students were asked to ________．
A．put together words of similar meanings
B．remember words and their meanings
C．show their knowledge of words
D．make up lists of related words
3.Which of the following may be easier to remember?
A．Themes learned right before the test．
B．Rules from personal experiences．
C．Words learned before a good sleep．
D．Ideas stored together in the brain．
4.What may be the importance of the research?
A．It shows that sleep may help us manage information．
B．It helps find out the common themes of words．
C．It tells us that more sleep can improve health．
D．It proves the value of old-fashioned advice．
高三英语阅读理解中等难度题查看答案及解析
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Scientists who discovered a new way of generating electricity from water say they may have come across an alternative source of clean energy to rival wind and solar power.
The breakthrough, which scientists say is the first new way to generate electricity in 160 years, could lead to batteries that use water instead of poisonous substances.
The scientists made the discovery when they were investigating what happens when tap water is forced through extremely narrow glass tubes. Water squeezed down the tubes, each of which was narrower than a tenth the thickness of a human hair, generating a small electric current that ran the length of the tube. To produce a larger electric current, the team tried forcing water through a glass water filter(滤水器)that contained thousands of narrow channels lined up side by side. “When we took a syringe(注射器)of water and squeezed it through the filter, we got enough power to light a light bulb,” said Larry Kostiuk of the University of Alberta in Canada. “The harder you push the syringe, the more electric current you get.”
The current is produced because of an effect in the glass tubes. When they are filled with water, positively charged ions(阳离子)fixed in the tubes are washed away, leaving a slight negative charge on the glass surface. When water is then forced along the tube, the surface repels negatively charged ions in the water while positively charged ions are attracted down the tube. The result is a net flow of positively charged ions that sets up an electric current.
According to Dr Kostiuk, no one has ever thought to use water to produce electricity in this way. “The last time someone came up with a way of generating electricity was Michael Faraday in 1839,” he said. “So this is the first new way of generating electricity in 160 years, which is why we are so excited about it.”
Dr Kostiuk says water batteries might one day be used to power mobile phones and calculators, but admitted that the engineering challenges might make other applications more realistic. “You’d need to be sure it wouldn’t leak, and you’d need to make sure it wouldn’t freeze,” he said.
More likely would be to install the electricity-generating devices where water is already being pumped, such as at city water filtration sites, he said. “It could compete with wind and solar power,” he added.
1.What does the passage mainly want to tell us about?
A. A kind of solar power discovered by scientists.
B. A kind of new energy source found in tap water.
C. The breakthrough to generate electricity 160 yeas ago.
D. A kind of new battery invented without poisonous substances.
2.The underlined word “repels” in Paragraph 4 is closest in meaning to _________.
A. rejects B. identifies C. attracts D. rebels
3.Why were the scientists extremely happy about their new discovery?
A. They were the first to find a new way to produce electricity.
B. They could make an electric current to light a light bulb.
C. Their discovery could be used to invent water batteries.
D. Their discovery was made 160 years earlier than Faraday’s.
4.What can we infer about potential water batteries?
A. They must be used to power mobile phones and calculators.
B. They have some possible disadvantages like water leaking.
C. They would be needed greatly at city water filtration sites.
D. They would be better than wind and solar power.
高三英语阅读理解困难题查看答案及解析
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In the US they focus on creative thinking skills, _____ in China they only focus on theory．
A．since B．when C．while D．now that
高三英语单项填空中等难度题查看答案及解析
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Scientists have discovered that 1. (stay) in the cold could help us lose weight. Researchers at the University of California found that exposure to the cold increases levels of a protein that helps form brown fat -- the type of fat that produces heat and keeps us warm. Brown fat burns energy, 2. helps us lose weight. White fat stores extra energy, which results 3. weight gain. The researchers said that because air conditioning and heating give us constant, 4. (comfort) temperatures, our body’s need for brown fat has decreased. They found that outdoor workers in northern Finland who 5. (expose) to cold temperature have 6. significant amount of brown fat when 7. (compare) to same-aged indoor workers.
The research was conducted on two different control groups of mice. 8. group was injected with the protein that helps create brown fat. This group later gained 30% less weight after both groups were fed high-fat diets. The researchers say this could be good news in the fight against obesity. People who are obese have 9. （low) levels of brown fat than thinner people. If you can somehow increase levels of this protein, you could 10. (possible) lose more weight even if eating the same amount of food.
高三英语信息匹配中等难度题查看答案及解析
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Scientists have found what look like caves on Mars(火星),and say they could be protecting life from the planet’s terrible environment.
Images of the Mars caves from Northern
Arizona University
The first caves discovered beyond the Earth appear as seven mysterious black dots on the pictures sent back by NASA’s Mars Odyssey orbiter.Each as large as a football field,they may be openings into natural caves below the Martian surface.
“If there is life on Mars,there is a good chance you’d find it in caves,”said Jut Wynne,one of the researchers who noticed the features while working on a US Geological Survey Mars Cave Detection Program.
Jonathan Clarke,a geologist with the Mars Society of Australia,yesterday described the discovery as exciting.
One photo taken at night by an infrared imager(红外线成像器) showed one hole to be unusually warm,suggesting hot air trapped during the day is flowing out.
“I said:‘Wow,that’s a cave’,”Dr.Clarke said excitedly.“People have been looking for these for a long time;now we have found them.”
He agreed such caves would be perfect places to hunt for life escaping from the bitterly cold,radiation-soaked(充满辐射的),dry surface.
“Tiny drops of water could collect inside,”he said.“If there are gases coming out,they could provide energy for a whole range of bacteria.A cave is also a protection from radiation;the surface of Mars is exposed to high levels of space radiation.”
The caves probably formed when tube-shaped lava flows(管状岩浆流) spread across the planet long ago.The outside of the tubes cooled,forming solid walls,while something hotter inside allowed the remaining lava to flow out,forming caves.
1.What does the passage mainly talk about?
A.How the caves were formed on Mars.
B.How scientists found these caves on Mars.
C.Caves on Mars may be full of hot air or a sign of life.
D.Scientists have completely recognized the surface of Mars.
2.We can learn from the passage that _______.
A.water has already been found on Mars
B.the scientists found all the caves at night
C.it is certain that there is life in these caves
D.the surface of Mars is bitterly cold,radiation-soaked and dry
3.According to the passage,Dr.Clarke was so excited because _______.
A.such caves could provide energy for life
B.they had finally found the caves on Mars
C.such caves would be perfect places to hunt for life
D.scientists had long been looking for these caves
4.Necessary conditions for life on Mars mentioned in the passage may include _______.
A.lava and energy
B.water and radiation from space
C.gases and lava
D.water and protection from radiation
高三英语阅读理解中等难度题查看答案及解析
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Scientists have been studying how people use money for long. Now they’re finding some theories may apply to one group of monkeys.
Researchers recently taught six monkeys how to use money. They gave the monkeys small metal disks(圆片) that could be used like cash and showed them some yummy apple pieces. The monkeys soon figured out that if they gave one of the disks to a scientist, they d receive a piece of apple in return.
If you think that is all the monkeys can figure out, you are wrong. Two researchers, Jake and Allison, acted as apple sellers in the experiments. The monkeys were tested one at a time and had 12 disks to spend in each experiment. Jake always showed the monkeys one apple piece, while Allison always showed two pieces. But that’s not necessarily what they gave the monkeys. The number of apple pieces given for a disk was determined at random.
Experiment One: Allison showed two pieces of apples but gave both pieces only half the time. The other half, she took one piece away and gave the monkey just the remaining piece. Jake, on the other hand, always gave exactly what he showed: one piece for each disk. The monkeys chose to trade more with Allison.
Experiment Two: Allison continued to sometimes gave two pieces and sometimes one piece. But now, half the time, Jake gave the one apple piece he was showing, and half the time he added a bonus. Guess what? The monkeys chose to trade more with Jake.
In the first experiment, the monkeys correctly figured out that if they traded with Allison, they’d end up with more treats. In the second one, when a monkey received two pieces from Jake, it seemed like again. When Allison gave the monkey only one piece instead of the two she showed, it seemed like a loss. The monkeys preferred trading with Jake because they’d rather take a chance of seeming to win than seeming to lose.
We also sometimes make silly business decisions just to avoid the feeling that we’re getting less, even when were not. Would you have made the same choices?
1.What conclusion might experts draw from the first experiment?
A. The monkeys show certain business sense.
B. Business theories can apply to all monkeys.
C. People are smarter in terms of finance.
D. It’s easy to teach monkeys how to trade.
2.What does a bonus in paragraph 5 refer to?
A. A metal disk.
B. An apple piece.
C. A chance.
D. A coin.
3.Why did the monkeys choose to trade more with Jake in the second experiment?
A. Because Jake always gave them two apple pieces.
B. Because the apple pieces from Jake were yummy.
C. Because they didn’t like the feeling of losing.
D. Because they get more apple pieces from Jake.
4.What could be the best title for the passage?
A. People’s Business Decision: Lose or Gain?
B. Moneky’s Business Sense: Smart or Silly?
C. Shopping for Bargain: Same or different?
D. Disk for Apple: Who to Trade with?
高三英语阅读理解中等难度题查看答案及解析
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Scientists from the United States say they have found fish and other creatures living under key waters in Antarctica. They made the announcement after completing three months of research at the Ross Ice Shelf, the world’s largest floating ice sheet.
The researchers hoped to find clues to explain the force of the melting ice and its effect on sea level rise. Reed Scherer and Ross Powell are with Northern Illinois University in DeKalb, Illinois. They just finished up their research on our southernmost continent. Money for the project came from America’s National Science Foundation.
“We chose a study site where, in the first year ,We went into the subglacial (冰川下的)lake and tried to understand the environment in there, both ecologically and in terms of the ice dynamics about how the lake operates ,and how the sediment(沉淀物) underneath the ice sheet operates, as well, because it’s the water and the sediment underneath the ice that controls how fast the ice is flowing into the ocean” says Ross Powell, who led the investigation. The team included scientists ,engineers, machinery and other supplies across the ice from the main U.S. scientific base at Mc Murdo Station to the researcher’s camp .The camp was near a subglacial lake ,where an earlier study took place,
Ross Powell says the latest study may provide evidence that can help predict the effect of climate change on rising sea levels.
“What we have found is that these are very sensitive areas to the stability of how dynamic the ice is and how fast the ice may react to increases of melting both from the ocean and the atmosphere.”
Among the new instruments built for the project was a powerful hot water drill. The researchers used the drill to dig down some 740 meters. They collected water ,sediment and other material from the grounding zone.
Working around the clock before the deep hole refroze, they sent a video camera down to the 400-square-meter undersea area.
Reed Scherer says the video images they saw in the Command Center were a total surprise.
“It’s a very mobile environment. The bottom is changing constantly. And so the things that we saw were all very mobile organisms, things that swim and some things that crawl. And obviously they are getting enough nutrition that they can thrive, Some of the little crustacean-like creatures called amphipods that we saw swam quite quickly and were quite active.”
This is the farthest south that fish have ever been seen. How did the creatures get here? What do they feed on? And what effect will the retreating ice have on them?
Ross Powell says the ice and sediment cores taken from the grounding zone can offer clues.
“We know that the ice is melting there at the moment and so by opening up the cores once they get back, we hope to be able to understand what the ice was doing in the past ,relative to what it is doing now. And because it is melting so fast or seems to be melting fast at the moment, we anticipate that there will he some differences that we’ll see in the history of the ice sheet from the sediment cores, once we open them up .”But Ross Powell says the work raises more questions than it answers.
1.Scientists conducted the three-month research at the Ross Ice Shelf with the intention of .
A. predicting how climate change influences rising sea levels.
B. finding out whether there are life forms existing deep under Antarctic ice.
C. proving the speed of ice flowing into the ocean is controlled by water.
D. discovering an explanation of the effect the melting ice has on sea level rise.
2.What made the researchers surprised when they saw the video images?
A. Researchers saw fish in the farthest south for the first time.
B.A video camera was able to work well under deep icy waters.
C. Sediment cores present differences in the history of the ice sheet.
D. The drill should dig down 740 meters to collect things.
3.From sediment cores taken from the grounding zone, scientists will probably know .
A. what the ice will do in the near future
B. the ice in the grounding zone is melting at the moment
C. some differences rarely exist in the history of the ice sheet
D. something about the creatures under icy water in Antarctic.
4.What can be inferred from the passage?
A. Scientists will conduct a follow-up study on the frozen continent.
B. No creatures once appeared or lived in icy water in Antarctica.
C. America’s National Science Foundation is in complete charge of the research.
D. Researchers have found how the sediment underneath the ice sheet operates.
高三英语阅读理解中等难度题查看答案及解析
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Scientists say they have used the gene-editing tool CRISPR to repair a person’s eyesight for the first time. The CRISPR tool makes it possible to change DNA to add needed genes or take some away if they lead to problems.
A patient recently had the procedure done for an inherited form of blindness. The operation took place at Oregon Health and Science University in Portland. “We literally have the potential to treat people who are essentially blind and make them see,” said Charles Albright. He is chief scientific officer at Editas Medicine in Cambridge, Massachusetts. Editas is one of the companies developing the treatment. Albright added, “We think it could open up a whole new set of medicines to go in and change your DNA.”
The people taking part in the study have a genetic condition that keeps the body from making a protein needed to turn light into signals to the brain, which leads to sight.
Scientists have found it difficult to treat the condition with usual gene therapy. So, they are aiming to edit or remove the mutation（突变）by making two cuts on either side of it. The hope is that the ends of DNA will reconnect and make the gene work as it should. Through a tube the width of a human hair, doctors put three drops of fluid containing the gene editing machinery just under the retina（视网膜）, which is the lining at the back of the eye that contains the light-sensing cells. Doctors believe they need to fix one-tenth to one-third of the cells to repair vision. In animal tests, scientists were able to correct half of the cells with the treatment, Albright said.
Some independent experts were hopeful about the new study. Dr. Kiran Musunuru is a gene-editing expert at the University of Pennsylvania. He said the treatment seems likely to work, based on tests in mice and monkeys. The gene editing tool stays in the eye and does not travel to other parts of the body. So, “If something goes wrong, the chance of harm is very small.” Musunuru said. “It makes for a good first step for doing gene editing in the body.”
1.Who can most possibly benefit from this new treatment?
A.Patients who are essentially color-blinded.
B.Patients who turn blind due to accidents or diseases.
C.Patients who are born with no ability to see.
D.Patients who lose their vision at a young age.
2.Which is Paragraph 4 mainly about?
A.The result of the treatment.
B.The theory of the treatment.
C.The difficulty of the treatment.
D.The disadvantage of traditional treatment.
3.What is likely to be discussed after the last paragraph?
A.The function of the gene-editing tool.
B.The limitation of the gene-editing tool.
C.The effect of the treatment on animals.
D.The research of the treatment on humans.
高三英语阅读理解中等难度题查看答案及解析