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Autism（自闭症） could be caused by a lack of protein（蛋白质） in the brain, new research suggests.
A third of cases are believed to be down to a lack of nSR100， which is important for normal brain development. Experts say this can cause mistakes in the wiring（布线） of the brain and possibly lead to autism.
Researchers from the University of Toronto lowered levels of the protein,which controls the building of cells（细胞），in mice. They found that a reduction in nSR100 by just half was enough to trigger typical autistic（自闭症的） behaviors. These include avoiding social activities and increased fear to noise.
This is the second study of the protein by the Canadian researchers. The first showed that nSR100 is reduced in the brains of autistic people.
Lead researcher of the study, Dr Sabine Cordes, said："We previously reported a connection between nSR100 protein levels and autism. But this time we show that reduced levels of this protein could really be the reason-that's a big deal. Just by reducing the nSR100 levels by 50 percent, we observe clear signs of autistic behavior."
Autism-which is known best for changing social behavior-is a mental disorder affecting more than one per cent of the population. While its origins are genetic（基因的），the real causes are known in only a very small number of cases.



What does the underlined "nSR100" in Paragraph 2 most probably mean？ ______

A. A normal brain development.
B. A kind of protein.
C. The brain of an expert.
D. The wiring of the brain.

Which of the people might have autism according to the third paragraph？ ______

A. Peter who is fond of sports with friends in the open air.
B. Paul who is noisy and interested in school activities.
C. Tom who is afraid of taking part in a birthday party.
D. Jim who is easily angry and unwilling to work hard at school.

Where does Dr Sabine Cordes probably come from？ ______

A. China.
B. The USA.
C. Germany.
D. Canada.

What can be inferred from the last paragraph？ ______

A. Autism can best change social behavior in a mental order.
B. Researchers have only understood a little about autism so far.
C. More than one percent of the population affect autism.
D. Researchers believe autism has nothing to do with gene.

Calling all tea lovers： the next time you reach for a cup of tea, try green tea-if you want to lengthen your life. That's according to a new study recently concluded by researchers with the Chinese Academy of Medical Sciences. Researchers found "habitual" tea drinkers-whom they defined as drinking tea at least three or more times a week-had longer and healthier lives than those who did not drink tea as regularly. But these benefits were only seen in those who drank green tea, not black tea.
To come to this conclusion, researchers analyzed 100，902 Chinese participants with no history of heart attack or cancer. They were divided into two groups, those who drank tea three or more times a week, and those who drank tea less than three times a week. Participants were then followed-up after seven years.
In the end, the researchers found that regular tea drinkers had a 20 percent lower risk of suffering from heart disease, and a 22 percent lower risk of dying from heart disease than those who never or seldom drank tea. Then, to look at the "potential influence of changes in tea drinking behavior," researchers about eight years later took a part of study participants-14，081 people-and assessed them after five years. Finally, they found those who continued to drink tea three or more times a week had a 56 percent lower risk of deadly heart disease.
But why is green tea more beneficial than black？ Senior author Dr. Dongfeng Gu said that green tea is rich in polyphenols（多酚）， as a previous study shows, which, "protect against cardiovascular（心血管的） disease and its risk factors." Black tea, on the other hand, is fermented（发酵）， during which process "polyphenols may lose their antioxidant effects."
"In our study population, 49% of habitual tea drinkers consumed green tea most frequently, while only 8% preferred black tea," he said. "The small percentage of habitual black tea drinkers might make it more difficult to observe strong associations, but our findings hint at a differential effect between tea types."



What is paragraph 2 mainly about？ ______

A. The research process.
B. The research purpose.
C. The research subjects.
D. The research findings.

What does the underlined phrase "hint at" in paragraph 5 probably mean？ ______

A. Assess.
B. Examine.
C. Produce.
D. Indicate.

Which of the following is the best title for the text？ ______

A. Green Tea or Black Tea, That's a Question
B. Tea Drinking： a Common Practice in China
C. Green Tea Drinkers may Enjoy a Longer Life
D. Tea Time： Relaxing, Refreshing and Rewarding

Climate change leads to threat to the world's sandy beaches, and as many as half of them could disappear by 2100， a new study has found. Even by 2050 some coastlines could be unrecognizable from what we see today,with 10% to 12% facing severe erosion（侵蚀）.
Using updated sea level rise predictions, the researchers analyzed how beaches around the world would be in a future with higher seas and more damaging storms. They also considered natural processes like wave erosion, as well as human factors-like coastal building developments, all of which can affect a beach's health. The study found that sea level rise is expected to outweigh these other factors, and that the more heat-trapping gases human put into the atmosphere, the worse the influences on the world's beaches are likely to be.
It's hard to overstate just how important the world's beaches are. They cover more than one third of the world's coastlines, and protect coastal areas from storms. Beaches are also important economic engines, supporting relaxation, tourism and other activities. And in some areas, the beach is more than a vacation destination. In places like Australia, life near the coast revolves around the beach for much of the year.
Some of the world's most popular beaches are already taking action. Places like Miami Beach are trucking in thousands of tons of sand to patch up（修复） badly eroded shorelines, while others have built sea walls and breakwaters in an attempt to hold precious sand in place. But the financial and environmental costs of these projects are huge, and scientists say rising seas and more powerful storms, supercharged by a warmer climate, will make thisa losing battle.
However, the researchers did find that humans have some control over what happens to the world's beaches. If the world's governments are able to stick to modest cuts to heat-trapping gas pollution, the researchers found that 22% of projected beach losses by 2050 could be prevented, a number that grows to 40% by 2100 if greenhouse gases are limited.



Which is the biggest contributor to severe beach erosion？ ______

A. Damaging storms.
B. Wave erosion.
C. Coastal building.
D. Sea level rise.

What can we infer from Paragraph 3？ ______

A. It is hard to protect coastal beaches.
B. One third of storms take place near beaches.
C. Beaches are of great significance to our lives.
D. Most Australians live on beach tourism.

What does the underlined word "this" refer to in Paragraph 4？ ______

A. Popularizing the beaches.
B. Holding sand in place.
C. Reducing the project costs.
D. Stopping global warming.

What is the best title for the text？ ______

A. Half beaches could disappear by 2100.
B. Climate change is doing harm to our lives.
C. The beach is more than a vacation destination.
D. Governments are taking action to fight wave erosion.

Just as our bodies produce waste every day - which is why we need to shower and use the toilet - our brains produce harmful waste proteins. But how can our brains "shower" themselves？
A 2017 study found the answer. Researchers at the US University of Rochester studied the brains of mice and discovered that they cleaned themselves while the mice slept. A kind of fluid in the brain, called cerebral spinal fluid （CSF，脑脊液）， was found to increase dramatically during sleep, washing away waste proteins that had been building up between brain cells in waking hours. "This study shows that the brain has different functional states when asleep and when awake," Maiken Nedergaard,the lead researcher, told NBC News. It also explains why we can't seem to think clearly after a sleepless night while a good night's sleep leaves us feeling sharp and refreshed.
Now a new study, published on Oct 31 in Science, digs a little deeper into our brains' self-cleaning procedure. Instead of mice,this time humans were the test subjects. Researchers at Boston University,US，monitored the brain waves of 13 healthy adults who were sleeping, using accelerated MRI， which is capable of recording faster changes inside the brain than a regular FMRI machine. They found that every 20 seconds, blood flowed out of the brain, making room for a large amount of CSF to come in and "clean". This cycle coincided with the rhythm of the brain's slow waves - an electrical activity that happens when we're in deep sleep. It's still unknown how these brain activities are connected. But the fact that they are connected is exciting enough, since it allows researchers to piece together possible new explanations for misunderstood diseases. For example, slow-wave sleep has been proven to play a role in strengthening our memories. This may explain why people with Alzheimer's often have fewer and weaker slow brainwaves.
Based on this new study,there could be one more explanation for diseased brains：They are not clean. Nedergaard, leader of the 2018 study, is also excited about the new findings. "Maybe the most important take-home message is that sleep is a serious thing," she told Scientific American. "You really need to sleep to keep a healthy brain because it links electrical activity to a practical 'housekeeping' function."



What can we learn about CSF？ ______

A. It is a fluid which increases during the day.
B. It builds up between brain cells in waking hours.
C. It comes in the brain and washes away waste proteins.
D. It exists more in human brains than in mice brains.

Why did the researchers at Boston University use humans as the subjects？ ______

A. To know more about human brains' self-cleaning procedure.
B. To see how human brains function when they sleep.
C. To reduce the difficulty of the experiment.
D. To get more information about CSF.

What can the new findings contribute to？ ______

A. strengthening our memories.
B. explaining some misunderstood diseases.
C. helping cure Alzheimer.
D. keeping our house clean.

Which of the following is the best title for the text？ ______

A. Curing diseased brains
B. Feeling sharp and refreshed
C. Taking your sleep seriously
D. Cleaning in your dreams

Beijing is a rather strange city to many western people. One of my foreign friends told me that when he came to Beijing,at first he couldn't understand why most people wear masks when spring comes to Beijing. He thought people wanted to keep their appearance a secret. Well, one of the symbols of spring coming to Beijing is that more and more people start wearing masks. The reason for it is the arrival of so called "sandstorms".
It is said that each year sandstorms hit Beijing 4 to 5 times. The sand is brought to Beijing by wind from the western part of China. Tons of soil and dust travel hundreds of miles and blanket Beijing's streets, parked cars and apartment buildings. You would be amazed to see the ground has turned yellow overnight. The storm is so violent that you do not want to have a conversation with your friend on the road. If you open your mouth and then you close it, you may have the raw taste of sand in your mouth.
People in Beijing hate those storms. Sandstorms make the traffic jam in rush hours even more unpredictable,because the drivers have to drive slowly in order to have a clear view of the road conditions. Young students also hate sandstorms because whenever there is a sandstorm,they are not allowed to have any activities outside the classroom. It is so boring to sit in the classroom all day and the youngsters are so eager to go out and do some sports.
It is said that the closest desert is only 80 kilometers away from the city center.There is definitely much more to do for the local government to deal with the environmental problem.



Why do people in Beijing wear masks in the spring？ ______

A. Because they are rather strange.
B. Because there are serious sandstorms.
C. Because their appearance are not beautiful.
D. Because they want to keep their face a secret.

What does the underlined word "blanket" mean？ ______

A. cover.
B. cross.
C. destroy.
D. dry.

What do people have to do when the storm come？ ______

A. Drivers clean the road.
B. They hold some activities.
C. Youngsters go out to do sports.
D. Students stay in the classroom.

Which of the following would be the best title for the text？ ______

A. People in Sandstorms
B. How to Prevent Sandstorms
C. Sandstorms in Beijing
D. What to Do in a Sandstorm

For anyone still doubting the belief that our emotions impact our physical health, a new study from New Zealand should be able to settle the matter. It reports that the physical wounds of healthy seniors healed more quickly if they wrote about their most upsetting experiences.
This confirms the results of a 2010 study, and extends those findings to cover older adults - a group that is likely to suffer wounds （such as from surgery），and one with less access to other ways of lowering stress （such as exercise）.
Reported in the journal Psychosomatic Medicine,a research team led by the University of Auckland's Elizabeth Broadbent made a study featuring 50 healthy adults ranging in age from 64 to 97. They were asked to write for 20 minutes per day for three days on end.
Half were asked to write about the most upsetting experience in their life,describing their deepest thoughts, feelings, and emotions about the events, ideally not previously shared with others. The others were asked to write about their daily activities without mentioning emotions, opinions or beliefs.
Two weeks after the third day of writing, all participants received a standard 4mm skin biopsy （皮下活体组织检查） on their inner arm. The very tiny wounds caused by the biopsy were photographed regularly over the following days to determine the rate at which they healed.
On the 11th day after the biopsy,the wounds completely healed on 76.2 percent of those who had done the expressive writing. That was true of only 42.1 percent of those who had written about everyday activities.
"The biological and psychological mechanisms（机体）behind this effect remain unclear," the researchers wrote, noting that those who had done the expressive writing did not report lower stress levels or fewer depressive symptoms than the others in the control group. Even if they weren't consciously aware of feeling more relaxed or positive, the expressive writing appeared to have caused some sort of bodily reaction - probably involving their immune （免疫的） systems - that hastened their recovery.



What was the difference between the two groups of participants in the study？ ______

A. What they wrote about.
B. Where they wrote.
C. When they wrote.
D. How often they wrote.

According to the text, the experiment lasted ______ .

A. about three days
B. about ten days
C. about a month
D. about two weeks

The underlined word "hastened" in the last paragraph is closest in meaning to ______ .

A. showed
B. speeded
C. limited
D. ruined

What is the main idea of the text？ ______

A. Sharing with others can reduce stress
B. Skin biopsies are likely to cause wounds
C. Expressive writing heals physical wounds
D. Upsetting experiences impact our emotions

By the end of the century, if not sooner oceans will be bluer and greener thanks to a warming climate, according to a new study.
At the heart of the phenomenon lie tiny marine microorganisms （海洋微生物） called phytoplankton. Owing to the way light reflects off the organisms, these phytoplankton create colorful patterns on the ocean surface. Ocean color varies from green to blue, depending on the type and concentration of phytoplankton. Climate change will fuel the growth of phytoplankton in some areas, while reducing it in other spots, resulting in changes in the ocean's appearance.
Living on the ocean surface, Phytoplankton absorb carbon dioxide into the ocean while giving off oxygen. When they die, they bury carbon in the deep ocean, and help to adjust the global climate. But phytoplankton are allergic to the ocean's warming trend. Warming changes essential characteristics of the ocean and can affect phytoplankton growth.
Stephanie Dutkiewicz, a scientist in MIT's Center for Global Change Science, built a climate model that projects changes to the oceans throughout the century. In a world that warms up by 3℃， it found that multiple changes to the ocean color would occur. The model projects that currently blue areas with little phytoplanktor could become even bluer. But in some waters, a warming will make conditions suitable for phytoplankton, and these areas will turn greener. "Not only are the quantities of phytoplankton in the ocean changing," she said, "but the type of phytoplankton is changing."
And why does that matter？ Phytoplankton are the base of the food web. "If certain kinds begin to disappear from the ocean," Dutkiewicz said, "it will change the type of fish that will be able to survive." Those kinds of changes could affect the food chain.
Whatever color changes the ocean may experience in the coming decades will probably be too gradual and unnoticeable, but they could mean significant changes. "It'll be a while before we can statistically show that the changes are happening because of climate change," Dutkiewicz said, "but the change in the color of the ocean will be one of the early warning signals that we really have transformed our planet."



What is the major cause that directly results in changes in the ocean's color？ ______

A. The temperature of sea water.
B. The type and concentration of phytoplankton.
C. The oxygen given off by phytoplankton.
D. The amount of carbon dioxide in the area.

What can be learned from the passage？ ______

A. Phytoplankton have been used to control global climate.
B. Phytoplankton are of little significance in Dutkiewicz's research.
C. Phytoplankton are not sensitive to the warming trend in the ocean.
D. A warming trend helps phytoplankton grow and oceans may appear greener.

What is the main purpose of the passage？ ______

A. To describe the importance of phytoplankton.
B. To explain the effects of climate change on oceans.
C. To introduce a new approach to phytoplankton study.
D. To assess the consequences of changes in ocean color.

The biggest and the smallest of the world's animals are most likely to die out,according to a new analysis,with vertebrates（脊椎动物）in the so - called "Goldi-locks zone"-not too big and not too small-winning out. Action is needed to protect animals at both ends of the scale,they say. The research adds to evidence that animals are dying out on such a scale that a sixth extinction is considered under way.
One clue is body size. Research on birds and mammals has shown that those with larger bodies are more likely to go extinct. Yet,when the researchers made a database of thousands of birds,mammals,fish,amphibians（两栖动物）and reptiles（爬行动物）that are likely to be extinct,they found disproportionate （不成比例的） losses at the large and small ends of the scale.
"Surprisingly,we found that not only the largest of all vertebrate animal species are most threatened,but the very tiniest ones are also highly threatened with extinction," Prof. Ripple told BBC News.
Large animals,such as elephants, rhinos（犀牛）and lions have long been the target of protection efforts. However, fish, birds, reptiles and amphibians that are the giants of their kind, such as the whale shark,Somali ostrich（鸵鸟）and the Chinese giant salamander（蝶嫄），tend to be overlooked. Meanwhile,small endangered species -- such as frogs and shrews（MSSS）receive very little attention.
"I think, for the smallest species,first of all we need to bring more attention to them,because the larger ones get a lot of attention, but the smaller ones get very little," said Prof. Ripple.
In the study,vertebrates with the smallest and the largest bodies were found to be most likely to disappear, whether they were on land or living in oceans, streams or rivers.
Heavyweights are threatened mainly by hunting,while featherweights are losing out to pollution and cutting down forests. "Ultimately, reducing global consumption of wild meat is a key step to reduce negative impacts of hunting,fishing,and trapping on the world's vertebrates,"they write in Proceedings of the National Academy of Sciences.



What made the researchers feel surprised？ ______

A. A sixth of animals are dying out.
B. Small animals are in great danger.
C. Great losses of birds and mammals.
D. Big animals are likely to disappear.

What should we do first for the smallest species according to Prof. Ripple？ ______

A. Transform our habits.
B. Change our concepts.
C. Find ways to save small animals.
D. Take measures to stop pollution.

What presents the great threat to vertebrates according to the last paragraph？ ______

A. Loss of forests.
B. Climate change.
C. Human activities.
D. Environmental pollution.

What would be the best title for the passage？ ______

A. Size Matters When It Comes to Extinction Risk
B. Large Animals Are Badly in Need of Protection
C. Why a Great Number of Animals Are Dying out
D. What We Should Do to Protect Endangered Species

Jeremy grew up being active in sports. But he never thought about healthy eating until he found himself gaining weight several years after college. Last week,Jeremy hit a turning point when he found that he was too out of shape to play in a company football team. He decided to change his eating habits.
The first step Jeremy took toward healthy eating was to stop going to fast-food restaurants. Jeremy used to eat fast food as often as 4 times a week. To his surprise, he found that giving up fast food wasn't that difficult. Now, he says, "I don't even like it anymore." When Jeremy does go out to eat, he tries to pick menu items that he knows are healthier. He orders salads and lower-fat sandwiches instead of hamburgers,and he drinks water instead of soda pop. "I try to order things that are already prepared the way I would like them to be prepared."
Planning meals has been a key to Jeremy's success. It helps him avoid getting too hungry and eating fast food. Each week he plans what he will eat for each meal, and he shops for groceries（食品杂货）with his plan in mind. "It's a lot easier to make healthy choices when you're just planning ahead for it." Rather than cutting out certain foods, Jeremy sometimes includes his favourite foods in his eating plan. "That way I don't feel like I'm letting myself down by not sticking to my plan."
Jeremy's friends and family noticed when he started eating healthier. They have helped him to make a habit of his healthy eating changes. "It made me feel pretty good,especially when people started making comments about the changes I was making," he says. "You just get the positive energy."



What made Jeremy decide to change his eating habits？ ______

A. Higher food prices.
B. Weight gain in college.
C. Dislike of unhealthy foods.
D. Failing to join a football team.

What did Jeremy think of giving up fast food？ ______

A. It was too easy for him.
B. It made him uncomfortable.
C. It was not as difficult as he thought.
D. It meant stopping going out to eat.

What played the most important role in Jeremy's healthy eating？ ______

A. Eating less at mealtimes.
B. Making plans ahead of time.
C. Following his friends' advice.
D. Cutting out all unhealthy foods.

How does Jeremy feel about people's comments？ ______

A. Surprised.
B. Encouraged.
C. Worried.
D. Interested.

There are plenty of health benefits of spending time in the great outdoors. According to a study published in the International Journal of Environmental Health Research, people who grew up with access to nature may have better mental health as adults than those who did not.
To test their hypothesis（假设），researchers sent questionnaires to 3，585 adults aged 18 to 75 in four European cities on topics such as how often they visited natural spaces as children and now as adults. Participants were also given psychological test to determine the state of their mental health in the last month. Adults with low levels of nature exposure during childhood saw "significantly worse" mental health issues and did not view natural spaces as much importance in adulthood as those who spent more time growing up outside.
Researchers say that their findings show the importance of childhood exposure to natural spaces as it relates to developing an appreciation of nature and healthy psychological state in adulthood.
This is particularly significant, because almost three-quarters of Europeans currently live in urban areas with little access to green spaces. That number is expected to increase to 80 percent in the next three decades. Mental health has been shown to be negatively influenced by urban environments due to exposure to noise, crowds and a lack of green spaces among other things. Children who lead inactive lifestyles are more likely to have a lower quality of life and physical health.
"Many children in Europe lead an indoor lifestyle,so it would be desirable to make natural outdoor environments available, attractive and safe for them to play in," said study author Mark Nieuwenhuijsen, director of ISGlobal's Urban Planning, Environment and Health Initiative. "We make a call on policymakers to improve the availability of natural spaces for children and green schoolyards."



What inspiration do researchers take from their findings？ ______

A. the health of children's psychology.
B. the state of children's mental health.
C. the development of nature appreciation.
D. the importance of childhood exposure to nature.

What can we infer from Paragraph 4？ ______

A. Europeans prefer an inactive lifestyle.
B. European Children are in good physical health.
C. Europeans lack access to natural spaces.
D. European Children probably suffer lower quality of life.

What in the future is the study most likely to influence according to the last paragraph？ ______

A. Urban planning.
B. Economic policies.
C. Child education.
D. Local tourism.

What can be the best title for the text？ ______

A. Indoor Activities Are Good for Children's Growth
B. Living in Urban Areas Harms Psychological Health
C. An Inactive Lifestyle Means a Lower Quality of Life
D. Childhood Exposure to Nature Benefits Mental Health