Humans work hard to avoid viruses. Sick people are isolated, diseased animals are killed and fields of infected crops are fired up. Reviving(复活)an ancient virus would surely be a disaster.
But a new study led by Fiddamanfrom Oxford, challenges this conventional wisdom. It shows how the revival of an ancient virus can unlock the secrets of its evolution.
The virus in the study is Marek’s disease virus(MDV), killing more than 90% of chickens. Yet when it was discovered in 1907, MDV rarely caused death.
Dr Fiddaman wondered whether its new-found virulence(毒性)was a result of large structural changes. To find out, he and his colleagues got their hands on nearly 1,000 chicken bones from ancient times across Europe and Asia, some of them up to 2000 years old. Sections of DNA from these remains were mapped on to the ones of today’s virus.
As the authors pieced together the sets of genes of ancient MDV, however, they noticed that the genes were arranged identically to those in modern species. It suggests that the increased virulence resulted not from large structural changes, but from point mutations(突变). In particular, changes had occurred in the arrangement of a gene called MEQ, which has an essential role in tumour(肿瘤)formation.
This discovery suggests that the ancient MDV may not have been able to cause tumours. To test this assumption, Dr Fiddaman followed up with a daring experiment. He made the ancient form of the MEQ gene and shoot it into living chicken cells. It did not turn on any of the genes associated with tumour formation. In comparison, a modern MEQ gene quickly showed its tendency to cause tumours.
By combining ancient and modern genetic biology, the methods pioneered in the paper reveal how, and more importantly why, any virus mutates. That could help scientists tackle other viruses that pull on the purse-strings of farmers —by designing new vaccines(疫苗), for instance— or even to work out how to prevent another global pandemic.
1. What is widely acknowledged about the revival of an ancient virus?| A．It is a challenging task. | B．It reveals the virus evolution. |
| C．It means a disaster for humans. | D．It helps people fight diseases. |
| A．Point mutations in MEQ. | B．The occurrance of a new gene. |
| C．The reproduction of the ancient MDV. | D．Large structural changes in modern species. |
| A．By investigating a typical case. | B．By conducting a field survey. |
| C．By studying the related theories. | D．By doing a comparative experiment. |
| A．Viruses weaken gradually when they mutate. |
| B．The finding throws light on handling other viruses. |
| C．A global pandemic requires a world effort to end it. |
| D．Farmers will face more complex challenges than before. |
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【推荐1】I wished I had known earlier the fact that I was a low achiever because there was a reason beyond my control. Then I needn’t have worked so hard in my late twenties and early thirties. But I just didn’t know that. I was writing and writing. I was working for no other reason than to hear people praise me.
Most people who go through university read at least twice as fast as I do. I can never tell my left from my right. I avoid dialing a telephone if I can help it, because I sometimes have to try three times before getting the number right. I hear that recording “The number you have reached is not in service” more than any man on earth.
Despite my weaknesses I view my dyslexia (difficulty in reading) as a gift, not a curse(诅咒). Many dyslexics are good at right brain, namely abstract thought, and that is what my key of creative writing is. I’m starting with nothing and coming up with something that didn’t exist before. That’s my strong point. I owe my career to Ralph Salisbury, my writing instructor at the University of Oregon, who looked past my misspellings and gave me encouragement and hope. I just carried on and never looked back. I’m also very “visual”. This means nothing in school, but when I write books or scripts, I’m seeing everything in my imagination. I write quickly. I go like the wind and can get up to 15 pages a day. Writing is not the problem. I have no problem downloading; it is inputting where things get messed up.
The real fear I have for dyslexics is not that they have to struggle with messy input, but that they will quit on themselves before they finish school. Parents have to create victories whenever they can, whether it is music, sports or the arts. You want your dyslexic child to be able to say, “Yeah, reading is hard. But I have these other things I can do.”
1. From Paragraph 3 we can know that ______| A．The author was grateful to his writing instructor |
| B．The author often complained about his dyslexia |
| C．The author had trouble with both inputting and outputting. |
| D．Having problem in inputting, the author wrote slowly. |
| A．they should work as hard as himself |
| B．they had better choose to drop out of school |
| C．they should be constantly encouraged |
| D．they should put their hearts into reading |
| A．He who laughs last laughs best. |
| B．Where there is a will, there is a way. |
| C．Reading enriches the mind. |
| D．When God closes a door, somewhere he opens a window. |
| A．Open-minded and optimistic | B．diligent and generous |
| C．clever but selfish | D．kind but useless |
【推荐2】Researchers have found depression is linked to areas of the brain shrinking in size but when depression is paired with anxiety one area of the brain becomes greatly larger.
A new study, published in the Journal of Psychiatry and Neuroscience, looked at more than 10,000 people to find the effects of depression and anxiety on brain volume, The study shows depression has a pronounced impact on the hippocampus, the part of the brain linked to memory and learning, shrinking it.
In contrast, the study found that when depression and anxiety occur together, it leads to an increase in size of the part of the brain linked to emotions, the amygdala, “Many studies looking at the effects of depression on brain do not account for the fact that people who have depression often experience anxiety too,” study lead and Ph.D. researcher Ms. Daniela Oyarce said.
Depression is considered a serious medical condition worldwide, and one in six Ausualians currently experience depression, anxiety, or both, “We found people who have depression alone have lower brain volumes in many areas of the brain, and in particular the hippocampus,” Ms. Daniela Oyarce said. “This becomes even more relevant later in life because a smaller hippocampus is a risk factor for Alzheimer's disease and may speed the development of dementia.”
A particularly important finding of this research is that people who had both depression and anxiety had less shrinkage in many brain areas and even an increase in the amygdala. This indicates that the true effects of depression on the brain has been underestimated because of an opposite effect in the amygdala. “Anxiety lowers the effects of depression on brain volume sizes by three percent on average—somewhat hiding the true shrinking effects of depression,” Ms. Daniela Oyarce said.
“More research is needed into how anxiety lowers the effects of depression, but for the amygdala, perhaps anxiety leads to overactivity,” Ms. Daniela Oyarce added.
1. Which aspect of the brain is affected by depression?| A．Surface | B．Function | C．Shape. | D．Volume. |
| A．Repair. | B．Emotions. | C．Learning. | D．Language. |
| A．The risk caused by depression. |
| B．The symptoms of depression. |
| C．The current situation of patients with depression. |
| D．The relationship between depression and anxiety. |
| A．The amygdala will shrink. | B．The amygdala will increase. |
| C．The hippocampus will increase. | D．The brain volumes will shrink. |
【推荐3】For a wide range of diseases, diagnosis comes later in life for women than for men, according to a large Danish study. Researchers don’t know whether the later diagnoses are due to genetics, the environment, possible biases in the healthcare system - or some combination of reasons.
The study of health data from 6.9 million Danish people found that across hundreds of diseases, women on average were diagnosed when they were about four years older than the age at which the conditions were recognized in men. “We’re not just looking at one disease here, we’re looking at all diseases and we are looking at an entire population, from cradle to grave,” lead author Soren Brunak from the University of Copenhagen told Reuters Health by phone. On average, women received cancer diagnoses 2.5 years after men. They received diagnoses for metabolic diseases like diabetes 4.5 years later. “This actually surprised us quite a lot,” Brunak said. “Men generally have a tendency to get to the doctor later. So presumably the difference in onset is even larger.”
Brunak and his team considered incidence rates of diseases in the 18 broad categories of the ICD-10 diagnosis system managed by the World Health Organization. The study wasn’t designed to explain the causes of the differences. Another limitation is that researchers only looked at diagnoses made in hospitalized patients.
Dr. Noel Bairey Merz, director of the Barbra Streisand Women’s Heart Center at the Cedars-Sinai Smidt Heart Institute, who was not involved in the study, pointed out to Reuters Health that the study therefore lacks information on age at diagnosis for people who didn't require hospitalization. “On the other hand,” she said, “being hospitalized is a sign of a serious illness, so that adds significance to the diagnosis and supports that disease onset may be later in women.”
Brunak’s study, published in Nature Communications, showed that the bone-thinning disease osteoporosis was a notable exception to the trend. Here, women were typically diagnosed before they suffered a fracture, while the opposite was true for men.
“I am fascinated by this study, which generally confirms all that I present in my Stanford course on Sex and Gender in Human Physiology and Disease,”said Marcia Stefanick, Director of Stanford University’s Women’s Health and Sex Differences in Medicine Center.
1. What can we know from the research?| A．Women were diagnosed four years later than men for any diseases. |
| B．Only the adults were involved in the research. |
| C．On average, women were diagnosed later than men for the same disease. |
| D．Women tend to go to the doctor later than men. |
| A．spread | B．beginning |
| C．symptom | D．ending |
| A．Dr. Merz made proper comments on the research. |
| B．Dr. Merz was not willing to participate in the research. |
| C．Dr. Merz didn’t think much of the research. |
| D．Being hospitalized is a sign of getting a serious illness. |
| A．critical | B．uninterested |
| C．favourable | D．indifferent |
【推荐1】Cities are likely to be affected by overheating, thanks to something called the urban heat island effect. Cities tend to be short of trees, which provide shade, and they are covered with black pavement, which absorbs heat from the sun. Think of how it feels to wear a dark shirt versus a white shirt on a sunny day. A black shirt absorbs light, heating you up. But a white shirt reflects light, keeping you cool.
The average temperature in a city of a million or more people can be more than 5 degrees F hotter than surrounding areas. That extra 5 degrees can turn a hot day from uncomfortable to deadly. As temperatures rise, cities will be an especially dangerous place to be during a heat wave. To protect public health, city officials are going to make the city cooler.
As part of that effort, Los Angeles is coating its roads in CoolSeal, a gray paint that keeps streets and parking lots 10 degrees cooler than black asphalt（沥青）. It will help Angelinos save money during the summer, when air conditioning sends power bills soaring. And it will save lives by lowering temperatures and improving air quality. Hot weather worsens air pollution by turning car exhaust into smog, which can make life miserable for people with asthma（哮喘）and other breathing problems.
Of course, LA will have to do more than paint over a few streets to cool off the city. Angelinos will also need to plant more trees and apply white paint to rooftops—at least those not already covered in solar panels. While LA is a pioneer of reflective streets, other cities, like New York, are already experimenting with reflective roofs or, like Melbourne, lowering the temperature by planting trees. LA is hardly alone in its effort to stay cool.
“This is an urgent challenge, and it’s much bigger than one person,” said Mayor Garcetti in a recent statement. “Climate change is a fact of life that people in Los Angeles and cities around the world live with every day.”
1. Which of the following contributes to the urban heat island effect?| A．Planting more trees in the streets. |
| B．Covering the streets with white paint. |
| C．Applying reflective paint to rooftops. |
| D．Furnishing every house with air conditioners. |
| A．How to make the city cooler. |
| B．Where to wear a white shirt. |
| C．Why to coat the roads with black paint |
| D．When to cut off the electricity supply. |
| A．Increasing the indoor activities. |
| B．Promoting the sale of air conditioners. |
| C．Making life easier and more comfortable. |
| D．Reducing the number of cold days. |
| A．L.A. adopted many approaches to fight against the heat. |
| B．L.A. calls on people to fight against global warming. |
| C．More and more countries begin to plant trees in the streets. |
| D．L.A. is painting its streets white to keep the city cool. |
【推荐2】[1] In 1856, a British survey team measured the height of Qomolangma with the result of 8,840 meters above sea level. However, the exact measurement has never been settled. In 1955, the figure was adjusted by an Indian survey team to 8,848 meters, and later to 8,850 meters according to a US team in 1999. And in 2005, a Chinese team gained a height of 8,844 meters, but that result wasn't widely accepted either.
[2] On May 6, 2020, a 30-member Chinese survey team, equipped with the latest technology, including a Global Navigation Satellite System receiver and a radar to measure the mountain's snow cap, is determined to settle the dispute (争议).
[3] But measuring Qomolangma is no easy task. The average air temperature there is -29℃ and hurricane-like winds blow all the time. According to Li Guopeng, leader of the No.1 Geodetic Survey Team of China's Ministry of Natural Resources, despite advanced technologies we now have — the likes of robots and drones — it’s uncertain that they can operate smoothly under extreme conditions, which is why sending human experts to the peak is still necessary to ensure a precise reading.
[4] But ______
[5] The truth is that measuring the height of Qomolangma is much more than just getting that one particular number. Mount Qomolangma is the perfect window for observing crustal (地壳的) movements. Tiny changes to the peak's height can indicate whether the two plates, the Eurasian plate and the Indian plate, are heading toward or away from each other. The survey team will also get firsthand information about the condition of the snow and other natural materials at the top, which could be an indicator of climate change on the Tibet-Qinghai Plateau.
[6] It might be true that settling a dispute was the driving force for continued exploration, but the good thing is that we always end up discovering so much more.
1. What is Paragraph 1 mainly about?| A．The importance of Qomolangma. | B．The dispute of Qomolangma’s height. |
| C．The difficulty in measuring Qomolangma. | D．The change of Qomolangma’s height. |
| A．They can read and deal with the results precisely. |
| B．They might break down under unusual conditions. |
| C．They are the latest advanced technology in the world. |
| D．They will work properly without human’s instructions. |
| A．what is the process of China’s measurement? |
| B．how is the latest technology used for the research? |
| C．does a tiny difference really matter for a huge mountain? |
| D．do extreme conditions actually affect the measurement? |
| A．The depth of snowcap. | B．The diversity of natural materials. |
| C．The state of crustal movements. | D．The change of worldwide climate. |
| A．To recommend a good way to settle a dispute. |
| B．To show the history of measuring Qomolangma. |
| C．To advertise China’s latest advanced technology. |
| D．To stress the value of China’s latest exploration in Qomolangma. |
【推荐3】Researchers in Singapore found that eating mushrooms over twice per week could help prevent memory and language problems later in life.
According to the study, published in The Journal of Alzheimer's Disease, there is a unique antioxidant (抗氧化物质) present in mushrooms that helps protect certain brain functions.
Researchers observed 663 Chinese adults aged over 60 whose diets and lifestyles were tracked from 2011 to 2017. In the study, the participants were asked how often they ate six different types of mushrooms: oyster, shiitake, white button, dried, golden and tinned. The findings showed that eating more than two shares of mushrooms per week somehow lowered the chances of mild cognitive impairment (MCI) by 50% against those who ate fewer than one share.
MCI is a condition that can make people forgetful, affect their memory and cause problems with language, attention and finding the exact position of objects in space. Changes in behavior can be not very noticeable and not serious enough to be known as dementia (痴呆).
Participants who ate more mushrooms were found to perform better in thinking and processing exams and also exhibited a faster processing speed. The advantage was reportedly more apparent in those who ate more than two shares a week or more than 300 grams.
The scientists pointed out, however, that they have yet to put up a direct link between the fungi(蘑菇) and brain function.
The researchers also acknowledged that since this study mainly relied on self-reported information on mushroom intake and other dietary factors, further studies may be required. Still, the lead study author Lei Feng is encouraged by their findings. ''This relevance is surprising and encouraging, '' Lei said.
Mushrooms are one of the richest dietary sources of ergothioneine (麦角硫茵氨基酸) — a substance which we humans can’t make on our own.
1. What aspect of research did researchers mainly do in paragraph 3?| A．Culture of diets. | B．Existence of MCI. |
| C．The types of mushrooms. | D．The benefit of eating mushrooms. |
| A．It can affect memory seriously. |
| B．It can result in language problems. |
| C．It can make people easy to be lost. |
| D．It can reduce the chance of forgetfulness. |
| A．They love communicating with others. |
| B．Their thinking ability is quicker than the majority. |
| C．Their processing speed will be faster. |
| D．Their academic performance improves significantly. |
| A．A science report. | B．An advertisement. |
| C．Adult’s literature. | D．Scientific fiction. |
【推荐1】The latest Chinese mission to space has made Wang Yaping the first Chinese woman to perform a spacewalk. Before Wang, only 15 women globally had conducted spacewalks since 1984. In the 60 years during which humans have been launched into the orbit, an all-female mission tends to be avoided because it seems like a stunt to purposefully draw attention. But Shenzhou XIII’s six-month journey in space has left much curiosity about the differences between male and female astronauts. Despite great challenges, women’s bodies and minds are uniquely suited for space missions.
First, the weight advantage. Lower body weights are just a small part of it. The rest of the difference comes from the amount of food, oxygen, and other resources needed to keep smaller humans alive. On average, men require 5 to 25 percent more calories a day than women. Smaller people produce less waste, which lowers demands to recycle and remove it. So women are physically more efficient in the sense.
There are considerations beyond the physical conditions. Scientists found that men tend to do well in shorter-term, goal-oriented situations, while women are better in longer-term, steady circumstances, People in steady circumstances are more communicative. Women are born with the social skill, so they are more likely to get along well on long-time space missions.
Does this mean that there is no reason to send men on these missions？Not quite. Data suggests that mixed-gender(性别)teams are the most successful overall.
1. What does the underlined word “stunt” in paragraph 1 probably mean?| A．A silly mistake. | B．An eye-catching act. |
| C．A dangerous decision. | D．A meaningless effort. |
| A．Better social skills. | B．Lower weight. |
| C．More flexibility. | D．Less resource consumption. |
| A．Can Women Make History? | B．Women on “Manned” Mission |
| C．Women Are a Far Cry from Men | D．Chinese Space Mission by Women |
【推荐2】Kenya’s long-distance runners are among the best in the world. Is their food and daily routine (常规) a key to the secret of their success? We spent a week at a training camp with ten top athletes (运动员) to find out. This is what we discovered.
They eat five times a day:
08:00 Breakfast
10:00 Mid-morning snack
13:00 Lunch
16:00 Afternoon snack
19:00 Supper
The Kenyan runners’ food is based on bread, rice, potatoes, porridge, cabbage, beans and ugali (balls of cornmeal). Ugali is usually eaten with vegetables.
Meat is eaten in fairly small amounts, just four times a week. The athletes drink a lot of tea with milk and sugar. They get all the vitamins (维生素) they need from their food — they never take vitamin pills.
They usually train as a group twice a day. The first run is at 6 o'clock in the morning and the afternoon run is at 5 o'clock. They run 10 to 15 kilometres in the morning and 6 to 8 kilometres in the afternoon. Once a week, the two 1,500-metre runners in the group run shorter distances at higher speeds.
An amazing part of the Kenyan food is its richness in carbohydrates (碳水化合物). Every 24 hours, they have about 600 grams of carbohydrates to give them energy for their training. They only eat a little fat, most of it coming from the milk they have in their tea. They drink about a litre (升) of water every day. Surprisingly, they drink more than a litre of tea every day, too. They always eat soon after training.
Rest and sleep are also an important part of the athletes’ programme. They are always in bed early and they always get a good night’s sleep.
1. Why did the author go to the training camp?| A．To improve his running. | B．To report who are the best runners. |
| C．To learn from the athletes’ good habits. | D．To find out why the athletes do so well. |
| A．It starts at midmorning. | B．It happens before breakfast. |
| C．It is shorter than the second run. | D．It is led by two 1,500-metre runners. |
| A．They drink a lot of tea. | B．They eat five times a day. |
| C．They never take vitamin pills. | D．They take in a lot of milk and sugar. |
The Mystery
Nearly a thousand giant stone figures stand side by side on Easter Island, now a part of Chile. Called moai (MOH-eye) by the locals, the statues can weigh more than 80 tons—about as much as ten whales—and some stand as tall as a three-story building.
Scientists think islanders began creating the moai some 800 years ago to honor their ancestors. In land, scientists found a volcanic crater and dug out ancient tools there used to carve figures from the volcanic rock. But the crater(火山口) is far from where most of the statues now stand. And scientists know the people didn't have wheels or animals to move the rock giants.
So how did the stone figures travel as far as 11 miles from the crater to the island's coasts? Some ideas are pretty wild—people have suggested that the moai walked by themselves, or even that space aliens beamed down to lend a hand. Scientists struggled to Easter Island to find out the truth.
The Detectives
"Heave-ho!" cry a group of scientists as they pull on ropes tied to a huge statue. The investigators are seeking clues about the moai in one of Easter Island's green valleys. Wondering if the islanders could have transported the statues upright with just rope and muscle power, they wrapped three strong ropes around the forehead of a ten-foot-tall moai copy. With several people pulling each rope, they're able to rock the 10,000-pound figure side to side, moving it forward with every tug(拖拽). "The statue's shape makes this movement fairly easy," team leader Carl Lipo says.
In the past, researchers have tried other moving methods. One group tied rope to the top and base of an actual moai and attempted to drag it forward with twisting motions. Another team laid a real 13-foot moai onto a giant log and pulled the log forward. All the experiments shared one result: The investigators got serious pain!
The Evidence
Although various scientific sleuths (侦查) found ways to move the moai, researchers still don't agree on what really happened. Some of these techniques might have only worked over short distances and on flat land. Others would have damaged the moai.
Many people think the statues were laid horizontally on wooden sleds which were dragged with rope across log tracks. "This would have been the safest way to move the moai," archaeologist Jo Anne Van Tilburg says. "It explains why hardly any are damaged."
But the truth may never be revealed.(Experts are pretty sure, though, that aliens weren't involved.)After all, the islanders stopped making the statues at least 300 years ago, later hundreds of islanders left the island or caught deadly diseases brought by explorers. Many of the moai's secrets disappeared with them. Today the only remaining witnesses to the events are the moai themselves. And the lips of these stone-faced giants are sealed.
1. How many possible ways of moving the rock giants are mentioned in the passage?
| A．Three. | B．Four. | C．Five. | D．Six. |
| A．The moai was created by the islanders 800 years ago to wish for good luck. |
| B．Some of the rock giants were damaged while being moved to where they are now. |
| C．All the witnesses to the secrets of the moai were infected with deadly diseases and died. |
| D．The statues were made of volcanic rocks with some handmade tools by the locals. |
| A．temporarily on the ground |
| B．parallel to the ground |
| C．steadily on the ground |
| D．vertical to the ground |
| A．Investigation Under Way. |
| B．Mystery of the Stone Giants. |
| C．Ways of Moving the Stone Giants. |
| D．The Unrevealed Truth. |
