An 18, 000-year-old human genome has been sequenced as a consequence of genetic research of ancient African skeletons, revealing information as to how the continent’s former people lived, migrated, and reproduced.
In general, DNA cannot survive in Africa’s heat and damp for lengthy periods of time, and researchers have never previously sequenced a sub-Saharan African human genome older than 9,000 years. The authors of this new study, on the other hand, regained genetic material from six people buried between 5, 000 and 18, 000 years ago.
They also looked at the records of 28 previously reported individuals found at burial sites around the continent, and these 34 people were from three unique source populations originating in northeastern, central, and southern Africa after studying their DNA. This means that the continent was originally inhabited by three distinct groups who must have lived in remote areas for long periods of time. The combination of these three branches, on the other hand, suggests that genetic information was exchanged between the three populations before 20, 000 years ago.
According to the authors of the study, this process began around 50, 000 years ago, because archaeological records suggest an increase in the movement of products over great distances around this time. People are thought to have started having offspring with partners from far-away places as trading networks grew across the continent.
However, the genomic data shows that this long-range DNA interchange began to decline some 20, 000 years ago, implying that humans began reproducing with their immediate neighbors at that time. According to the study’s authors, it may be due to the Last Glacial Maximum, when climate change may have limited people’s mobility and pushed them to become more sedentary.
In a statement, study author Jessica Thompson noted, “At first, people found their mates from a wide geographic pool. Further down the line, people valued partners who lived closer to them and were perhaps more culturally similar.” Co-author Elizabeth Sawchuk added, “Perhaps it was because previously established social networks allowed for the movement of information and technologies without requiring people to migrate.”
1. What is the challenge of the DNA study in Africa?| A．Hot and wet climate. | B．Limited technology. |
| C．Too many cultural exchanges. | D．Complex human genomes. |
| A．Climate change. | B．Archaeological records. |
| C．Trades with distant groups. | D．Development in technology. |
| A．Stable. | B．Diverse. | C．Active. | D．Reproductive. |
| A．Distant social exchange was booming 50, 000 years ago. |
| B．Long-ranged DNA interchange started to occur 20, 000 years ago. |
| C．Communication with people from similar cultures was always favored. |
| D．Migration declined when social networks for information became mature. |
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【推荐1】The secret to happiness is keeping busy, research has found.
Keeping the mind occupied with tasks — no matter how meaningless — keeps off negative emotions, the study found.
However, the bad news is that humans are seemingly born to be lazy in order to save energy, according to Professor Christoper Hsee, a behavioral scientist at Chicago University.
In a study, 98 students were asked to complete two surveys. After they had completed the first, they were made to wait 15 minutes to receive the next one. They were given a choice of either handing in the first survey nearby or at a more distant location they had to walk to. Whichever option they chose, they received a chocolate bar. It turned out that approximately two-thirds (68 students) chose the lazy option. Those who had taken the walk reported feeling happier than those who had stayed put.
Prof. Hsee concluded that keeping busy helped keep people happy. He said the findings, reported in the journal Psychological Science, had policy implications.
“Governments may increase the happiness of idle citizens by having them build bridges that are actually useless,” he proposed.
At the individual level, he advised, “Get up and do something. Anything. Even if there really is no point to what you are doing, you will feel better for it.” He added, “Incidentally, thinking deeply or engaging in self-reflection counts as keeping busy, too.”
“You do not need to be running around. You just need to be engaged, either physically or mentally.”
1. Keeping busy can make people happy because ______.| A．it can help people get rid of laziness | B．it can make people sleep better |
| C．it can help get rid of negative emotions | D．it can give people a sense of achievement |
| A．Everybody is born to be happy. |
| B．Only by keeping working all the time can you gain happiness. |
| C．Prof. Hsee’s findings were reported in Psychological Science. |
| D．Keeping busy goes against human nature. |
| A．To explain what happiness is. | B．To advise people not to sit around. |
| C．To advise people to do what they like to. | D．To show people how to take life correctly. |
【推荐2】SO THAT’S WHY WE CALL THAT THAT
In 1997, two smarty-pants, needing a name for their new data-index website, came up with “googol”, which is the number one followed by a hundred zeroes. Perfect! But as they typed Googol into a domain-name search engine, they committed a critical mistake. And the mistake stuck. Don’t believe us? Google it. Meanwhile, here are the stories behind other brand names.
Triscuit ► ELECTRICITY BISCUITS
Triscuit, a snack cracker, is short for “electricity biscuit”, because the first ones were proudly produced with hydro-electric power.
Häagen-Dazs ► NOTHING
Häagen-Dazs is short for... absolutely nothing. Reuben Mattus, who moved to Brooklyn from Poland, created the ice cream company in 1959. He wanted to give his company a Danish-sounding name in honour of Denmark’s reputation during the World War Ⅱ and settled on this nonsense phrase.
Nike ► VICTORY
Nike was named for the Greek goddess of victory. Legend has it that the shoe company’s famous “swoosh” logo represents the fleet-footed goddess’s wings.
Adidas ► ADI DASSLER
Adidas is an abbreviation of “Adi Dassler”, one of two Dassler brothers from Germany who founded competitive shoe empires after the World War Ⅱ (Adi’s brother Rudi founded Puma).
Lego ► PLAY WELL
Lego, a children’s toy that consists of small colored bricks that fit together, is a contraction of the Danish phrase leg godt, meaning “play well”.
1. Why does the author mention the story of Google in Paragraph 1?| A．To arouse curiosity of the brand names. | B．To classify the following brands. |
| C．To introduce a wonderful search engine. | D．To help search for information. |
| A．Nike. | B．Adidas. | C．Triscuit. | D．Häagen-Dazs. |
| A．Adidas was founded during the World War Ⅱ. |
| B．The founders of Adidas and Nike were brothers. |
| C．The stories behind Lego and Häagen-Dazs relate to Danish. |
| D．The first Triscuit biscuits were proudly made with solar power. |
【推荐3】People depend on insects to pollinate the plants that make many of the fruits, nuts and vegetables we eat. Past studies had shown urban air pollution might veil the smells insects use to find flowers. Computer models predicted this would cause problems for insects, seeking flowers for a meal. But scientists weren’t sure that would happen in real life.
James Ryalls, a biologist, and his team decided to find out if it would. Working in a field, his group crafted a system made up of large rings. Each area was open, so nearby insects could fly into it. The researchers pumped pollutant gases into these rings. Then during each field season, the scientists recorded how many times pollinators visited the flowers in each ring.
“The results were much more severe than we thought,” Ryalls says. Adding pollution “caused up to 90 percent fewer insects to be able to find the flowers that they need for food,” he says. This was in comparison to the pollutant-free rings. In some cases, only some 30 percent of the pollinating insects even entered the circles with polluted gases.
Counting insects proved easier than getting the pollution into the rings, notes Ryalls. He spent much of his time working on parts of the system that needed fixing. Along the way, gas spills occurred. “By the end of each summer experiment I smelt like a petrol station,” he says. One effect: “Insects now avoid me.”
Later, they counted seed pods on the plants. Overall, only around seven in every 10 flowers had been pollinated. That means there were far fewer seeds in polluted circles. If these were fruit or vegetable plants, there would have been far less food produced.
This study focused on insects finding flowers. But insects also use smells for communication and attracting mates. If air pollution covers those smells too, these tiny animals might face more threats to their survival.
1. What does the underlined word “veil” in Paragraph 1 probably mean?| A．Add. | B．Mask. | C．Release. | D．Form. |
| A．They counted insect visits to flowers. | B．They studied different polluted gases. |
| C．They drove some insects into the rings. | D．They pollinated flowers by themselves. |
| A．Pollution can result in fewer flowers. | B．Insects are afraid of the rings in the field. |
| C．Insects struggle to find flowers in polluted air. | D．Plant flowers depend on insects to pollinate. |
| A．The aim of the study. | B．Ways to help pollinators. |
| C．Insects’ various survival skills. | D．Insects’ means of communication. |
【推荐1】Emerging economies struggled to grow through the 2010s and pessimism covers them now. People wonder how they will pay debts during the COVID-19 and how they can grow rapidly as they did in the past in an era of deglobalisation (去全球化).
The freshest of many answers to this issue is the fast-spreading digital revolution. The digital revolution is already as progressive in emerging economies as developed ones. Among the top 30 nations by income from digital services as a share of gross domestic product(GDP), 16 are in the emerging world. Indonesia, for example, is further advanced by this measure than France or Canada. And since 2017, digital income has been growing in emerging countries at an average annual pace of 26 percent, compared with 11 percent in the developed ones.
How can it be that poorer nations are adopting common digital technologies faster than the rich? One explanation is habit and its absence. In societies filled with physical stores and services, customers are often comfortable with them and slow to abandon the providers. In countries where people have difficulty even finding a bank or a doctor, they will jump at the first digital option that comes along. Outsiders have a hard time grasping the impact digital services can have on underserved (服务不足的)populations. Nations lacking in schools, hospitals and banks can quickly bridge these gaps by establishing online services. Though only 5 percent of Kenyans carry credit cards, more than 70 percent have access to digital banking.
It’s early days, too. As economist Carlota Perez has shown, tech revolutions last a long time. Innovations like the car and the steam engine were still transforming economies half a century later. Now, the fading era of globalisation will limit the number of emerging markets, but the era of rapid digitisation has only just begun. This offers many developing economies a revolutionary new path to catch up with the living standards of the developed world.
1. What can we know about the digital revolution?| A．It increases people’s debts in deglobalisation. |
| B．It prevents emerging economy from developing. |
| C．It advances in emerging and developed economies. |
| D．It develops most rapidly in Indonesia in terms of GDP. |
| A．In economies lacking in online services. |
| B．In countries short of basic physical facilities. |
| C．In nations with adequate stores and services. |
| D．In societies easy to access doctors and banks. |
| A．Stable. | B．Hopeful. | C．Depressing. | D．Challenging. |
| A．Digital technology saves emerging economies. |
| B．Deglobalisation limits technology revolutions. |
| C．Emerging economies struggle in the pandemic. |
| D．Digital revolution grows better in globalisation. |
【推荐2】Guests arriving at the Aloft Hotel in Manhattan or one in Silicon Valley will soon be able to do something hotels have dreamed about offering for years: walk past the check-in desk and enter their rooms by using a smartphone as a room key. The boutique hotel brand from Starwood to Hotels & Resorts Worldwide Inc. plans to offer this feature at two hotels before the end of the quarter.
Starwood officials are hoping this will be one of the biggest technological changes in the industry since free Wi-Fi. “We believe this will become the new standard for how people will want to enter a hotel.” says Frits van Passchen, Starwood’s CEO.
Not everyone is so sure. Past attempts to use technology to streamline the check-in process have had mixed results. Robert Habeeb, president of the First Hospitality Group, says he pulled out check-in desks at two of his Holiday Inn hotels after finding that most guests ignored them. He found that many travelers will talk with a staff member and ensure their room has the right view or location, or to try for an upgrade. Other guests may still want to be greeted when they arrive.
Hotels have never been known for being in the forefront of technology, partly because many hotels are owned and managed by small companies. Many hotel operators, though, have been searching for ways to remove the bottlenecks (瓶颈) at a hotel’s front desk. “Everybody has to check in, but we are all doing it pretty much the same way we were 100 years ago,” says Christopher Nassetta, CEO for Hilton Worldwide holdings Inc. “It’s something we are seriously addressing.”
Yet it is still not clear that virtual keys will do better than previous attempts to beat traditional check-ins. An effort several years ago to allow guests to enter rooms with the magnetic strip (磁条) on their credit cards never became popular. Guests worried about security and were unwilling to give their kids credit cards instead of room keys.
1. According to the first two paragraphs, which of the following is NOT true?| A．The new room key may become a new standard of choosing a hotel. |
| B．Hotel officials hope the new room key will be a great change in hotel industry. |
| C．Aloft of Hotel in Manhattan will allow guests to use a smartphone as a room key. |
| D．All Starwood Hotels plan to offer the new room key before the end of the quarter. |
| A．unify | B．identify | C．simplify | D．beautify |
| A．it’s a good idea to cancel check-in |
| B．the way of check-in needs to be changed |
| C．the management of hotel needs to be improved |
| D．it depends on the hotel operators to update technology |
| A．secure | B．negative | C．bright | D．uncertain |
【推荐3】Have you ever wondered what wild animals do when no one is watching? Scientists have been able to record the “private” moments of wildlife with leading-edge technology. Low-cost, dependable and small modern cameras are of big help.
Cameras placed in hard-to-reach places have taken videos of everything from small desert cats to later snow loving felines (猫科) in the northern Rocky Mountains. These cameras are important tools to learn new information on wildlife.
Some videos help scientists see the effects of climate change. For example, the desert animal javelin and the tree-loving coatimundi have been caught on cameras north of their normal home. This could mean global warming is enlarging their living area northward.
Researchers use cameras along with global positioning systems, or GPS. They attach GPS devices (设备) to mule deer and antelope in and around Yellowstone National Park. Then they can record their movements, or migrations (迁移) . These cameras can be left in very rural (荒野的) areas for days, weeks or even month. They can provide information on how many animals are moving over a given period of time.
Rural video can show details about animal behavior, such as the calls made by migrating. Also some cameras record animal life and show everything from bison in Saskatchewan, Canada, to the underwater weed forest off California’s Channel Islands.
However, rural cameras have their problems too. Animals such as wolverines and bears sometimes attack them. Scientists do not know if the attacks are the result of anger or interest. Also, the devices have become popular tools to help hunters look for animals. Some people argue that it is unfair to use the cameras that way. Even with such problems, rural cameras are clearly an important scientific tool in researching wild animals.
1. Which of the following helps scientists know about climate change?| A．How active animals are. | B．What animals eat. |
| C．Where animals go. | D．When animals move. |
| A．Under water | B．In the field |
| C．On GPS devices. | D．On wild animals. |
| A．They affect animals' search for good. |
| B．They make wild animals puzzled. |
| C．They make animals attack one another frequently. |
| D．They might bring danger to animals. |
| A．Cameras Record Animals in the Wild | B．Every Coin Has Two Sides |
| C．Animals No Longer Have Secrets | D．An Invention Makes Animals Mad |
【推荐1】Islands in the world are famous for different things. But Hawaii is special for its variety of features. Beautiful sandy beaches, active volcanoes, a great canyon（峡谷）and special history and culture add up to create its famously romantic atmosphere.
Formed by volcanoes at the bottom of the sea, the Hawaii Islands are like a necklace in the middle of the Pacific Ocean, 3,700 kilometres off the west coast of America. There are eight main islands in the group, including Hawaii Island ( or Big 1sland ), Maui, Kahoolawe, Lanai, Molokai, Oahu, Kauai, and Niihau.
Hawaii Island, the youngest and biggest island ,was formed 430,000 years ago and is still growing.Kauai, the oldest, was formed 5.1 million years ago. For tourists, the sight of the lava that still flows from some of the volcanoes down to the sea, is a major attraction.
The state of Hawaii is the newest state in the US. In 1898 , the islands joined the US. In modern history, it will always be remembered for the attack on Pearl Harbor by the Japanese air force in 1941.
Over 1,000 years ago, the islands were settled by Polynesians. Captain James Cook led the first group of Westerners there in 1778.
Native Hawaiians have a special culture and language. Although nowadays English is the official language of Hawaii, folk music and dancing are still widely practiced. The traditional dance of the islands is the hula, a Hawaiian word that means dance.
Hawaii's reputation for romance was spread when Hollywood started to use its typical music in movies in the 1960's.
Today, Hawaii is famous for its mix of cultures. Chinese, Japanese and Filipinos all live there.
Chinese arrived in the islands as early as the late 18th century. Dr. Sun Yat-sen, the famous Chinese revolutionary, grew up there,
Everyone in Hawaii is a member of an ethnic minority and generally they exist in pleasant harmony of races and cultures.
1. What directly led to the appearance of the Hawaii Islands?| A．The beautiful sea. |
| B．The undersea volcanoes. |
| C．The separation from Mexico. |
| D．The coral reefs. |
| A．The Hawaii Islands are all formed 5. 1 million years ago. |
| B．The Hawaii Islands were governed by Japanese in 1941. |
| C．Hawaii is an area with one nation. |
| D．Hawaii is a famous tourist destination. |
| A．To introduce the variety of features of the Hawaii Islands. |
| B．To introduce the history. and culture of Hawaii. |
| C．To attract the tourists to visit there: |
| D．To show the author's experience in Hawaii. |
【推荐2】Ants have the ability to sniff out cancer cells in humans, a new study has discovered, suggesting they could be used for cancer diagnosis in future.
Researchers from the French National Centre for Scientific Research (CNRS) discovered that ant species Formica fusca (丝光褐林蚁) has a well-developed sense of smell. It was able to distinguish cancer cells from healthy cells in humans, thanks to their sense of smell, limited trials revealed. But more clinical tests must be carried out before they could be used in clinical settings like hospitals, the team said.
To conduct their research, the scientists performed tests with 36 ants, smelling cells under a laboratory setting. First, the specialists exposed the ants to the smell of a sample of cancerous human cells. This smell was then associated with a reward of sugar solution. In a second step, the researchers exposed the ants to two different smells. One was a new smell and the second was the smell of the cancer cells. Once this test was successful, the researchers exposed the ants to different cancer cells. As such, the scientists found that ants distinguished between cancer and healthy cells.
After training, Formica fusca ants are able to detect organic compounds (混合物) released by cancer cells. “This first study shows that ants have high potential, are capable of learning very quickly, at lower cost, and are efficient,” points out CNRS. This isn’t the first time that scientists have used the animal sense of smell to locate cancer cells. “Dogs’ noses are well suited for medical diagnosis and used for the specific detection of cancer,” the researchers explained. However, training them to do so requires several months to a year. “On the other hand, insects can be easily raised in controlled conditions, and hundreds of individuals can be trained with very few trials,” the researchers pointed out. “Our approach could potentially be applied to a range of other complex smell detection tasks including the detection of explosives, spoiled food, or other diseases.”
1. What can we learn about Formica fusca?| A．It has a sharp sense of smell. | B．It can diagnose ants’ illnesses. |
| C．It faces a challenge of surviving. | D．It has been used in clinical settings. |
| A．The number of ant species. | B．The different smells of cells. |
| C．The association between cells. | D．The time exposed to cancerous samples. |
| A．Diagnosis accuracy. | B．Low cost. | C．Scientific interests. | D．Smelling ability. |
| A．To appeal to people to protect ants. | B．To argue if ants are sensitive to cancer cells. |
| C．To introduce the ants’ ability of curing cancers. | D．To inform the ants’ special skill to distinguish cells. |
【推荐3】Time is running out for coral reefs as the climate gets hotter. So scientists are searching the globe for corals that are better at enduring heat, Now, new research shows how those “super corals” can survive: less roommate drama.
Reefs depend on a crucial partnership between the corals and the algae (海藻) that live in the corals’ tissue, The algae make food for the corals using sunlight and in exchange, get a nice spot to live. But when oceans heat up, that relationship goes bad, and the corals kick the algae out, Without their roommates, corals can die, turning a ghostly white, bleached (白化) color.
Still, some corals seem to resist bleaching better than others, A new study shows that those corals depend on algae that are better at tolerating heat. Researchers hope that pinpointing these abilities will help develop new conservation tools to preserve the world’s reefs as temperatures rise. About 1/4 of all marine life rely on coral reefs in some way, along with half 1 billion people around the world also depend on reefs for their food and livelihoods.
“Heat stress can kill a lot of corals really fast,” says Kate Quigley, a research scientist at James Cook University and the Minderoo Foundation in Australia. “I hope that nature does have some mechanisms to get us through the next few years while we get our act together.”
While the hope is that those algae could also aid in reef conservation in the future, researcher Patrick Buerger says it’s likely that it wouldn’t help all coral species. And even the toughest corals can only endure so much. Currently, the world is on track for just under 3degrees Celsius of warming by 2100, a level that would wipe out nearly all coral reefs.
“The action has to be on climate change,” he says. “This is a short-term solution that might buy some time for corals to adapt. But the main focus has to be on climate. There’s not a silver bullet to the problem.”
1. What is the feature of super corals?| A．Sun-loving. | B．Long-living. | C．Good-looking. | D．Heat-bearing. |
| A．Habitat. | B．Food. | C．Sunlight. | D．Friendship. |
| A．The population of marine life. | B．The importance of coral reefs. |
| C．The seriousness of global warming. | D．The living conditions of coral reefs. |
| A．It is useless | B．It is the last hope. | C．It is temporary. | D．It is the silver bullet. |
