When prehistoric man arrived in new parts of the world, something strange happened to the large animals. They suddenly became extinct. Smaller species survived. The large, slow-growing animals were easy game, and were quickly hunted to extinction. Now something similar could be happening in the oceans.
That the seas are being overfished has been known for years. What researchers such as Ransom Myers and Boris Worm have shown is just how fast things are changing. They have looked at half a century of data from fisheries around the world. Their methods do not attempt to estimate the actual biomass (the amount of living biological matter) of fish species in particular parts of the ocean, but rather changes in that biomass over time. According to their latest paper published in Nature, the biomass of large predators (animals that kill and eat other animals) in a new fishery is reduced on average by 80% within 15 years of the start of exploitation. In some long-fished areas, it has halved again since then.
Dr. Worm acknowledges that the figures are conservative. One reason for this is that fishing technology has improved. Today's vessels (船)can find their prey using satellites and sonar, which were not available 50 years ago. That means a higher proportion of what is in the sea is being caught, so the real difference between present and past is likely to be worse than the one recorded by changes in catch sizes. In the early days, too, longlines (多钩长线) would have been more filled with fish. Some individuals would therefore not have been caught, since no baited hooks (带饵钩)would have been available to trap them, leading to an underestimate of fish stocks in the past. Furthermore, in the early days of longline fishing, a lot of fish were lost to sharks after they had been hooked. That is no longer a problem, because there are fewer sharks around now。
Dr. Myers and Dr. Worm argue that their work gives a correct baseline, which future management efforts must take into account. They believe the data support an idea current among marine biologists, that of the “shifting baseline". The idea is that people have failed to detect the massive changes which have happened in the ocean because they have been looking back only a relatively short time into the past. That matters because theory suggests that the maximum sustainable yield （产量）that can be cropped from a fishery comes when the biomass of a target species is about 50% of its original levels。. Most fisheries are well below that, which is a bad way to do business.
1. The extinction of large prehistoric animals is noted to suggest that____.| A．large animals were easily hurt in the changing environment |
| B．small species survived as large animals disappeared |
| C．large sea animals may face the same threat today |
| D．slow-growing fish outlive fast-growing ones |
| A．fishing technology has improved rapidly |
| B．the catch-sizes are actually smaller than recorded |
| C．the marine biomass has suffered a greater loss |
| D．the data collected so far are out of date |
| A．people should look for a baseline that can't work for a longer time |
| B．fisheries should keep the yield below 50% of the biomass |
| C．the ocean biomass should restore its original level |
| D．people should adjust the fishing baseline to changing situation |
| A．biomass level | B．management efficiency |
| C．catch-size limits | D．technological application |
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【推荐1】Thanks to its cold environment, Antarctica remained largely untouched by humans for thousands of years. However, since the 1990s, the last true wilderness on the planet is becoming an increasingly popular destination for adventure-seeking tourists. Now, a new study states that the visitors may be leaving behind harmful bacteria(细菌) which could devastate the area’s native bird population.
Researchers believed that the Antarctic creatures were not affected by the danger due to the continent’s extreme weather. However, microbiologist Marta Cerdà-Cuéllar was not convinced this was true. She and some colleagues decided to examine samples from Antarctic birds for evidence of human bacteria. To ensure the waste was not polluted, the scientists had to collect it from the birds themselves. This was no easy task. If they missed catching a skua at first go, the bird never came close again.
It took the scientists four years, from 2008—2011, to collect fecal(粪便) samples of 666 adult birds from 24 local species. The results of their study revealed the presence of several types of human bacteria in the bird waste.
＂While we should do as much as possible to reduce transmission, it’s hard to believe that we will stop tourism and science at these sites, and so it is hard to believe that humans won’t continue to transmit pathogens(病原体).＂ said Kyle Elliott.
Experts, including González-Solís, believe the only way to prevent the mass destruction of the birds, is to introduce stricter regulations or, at least, obey the ones already in place. For example, while the Antarctica Treaty states clearly visitors carry their waste back home to protect the original environment, the regulation is rarely obeyed. Hopefully, officials will take steps to protect the easily hurt birds before it’s too late.
1. What does the underlined word ＂devastate＂ in Para. 1 mean?| A．Increase. | B．Destroy. | C．Affect. | D．Block. |
| A．This was not an easy task. |
| B．This proved their conclusion. |
| C．Their tempers contributed a lot. |
| D．They found polluted human bacteria. |
| A．Hopeless. | B．Difficult. | C．Impossible. | D．Delighted. |
| A．Make new strict rules. |
| B．Quit the Antarctica Treaty. |
| C．Take measures as soon as possible. |
| D．Encourage officials to strengthen cooperation. |
【推荐2】Climate Change and Other Human Activities are Affecting Species Migration
One of the reasons climate change is such an important topic is that it will affect the natural biological systems. Both plants and animals will have to respond to the changing climate. In some cases, this means adapting to higher temperatures. In other cases, the changes may be alterations in the rainfall, length of growing season, availability of resources, or other influences.
While some animals can adapt, others will have to migrate. Obviously migration can be apparent in mobile animals that will move to maintain a more or less similar climate to which they are accustomed.
But animal and plant movement does not occur in just a changing climate. It also has to make changes to the landscape that humans create. For instance, increased land allocation to agriculture or urbanization can create barriers for free migration. So, what scientists really want to know is how these two factors will affect the patterns of animal and plant movement.
Researchers in a study projected changes in the distribution of climatically suitable zones for projected future climates. Using a computer model, they projected how and when the species would migrate and they tracked the migration routes. The study incorporated a resistance to movement based on the amount of human alteration to the landscape. The analysis was similar to how the flow of electrons through a wire circuit is calculated. In fact, electronic circuit theory formed a basis for the calculations.
From their analysis, the authors identified several locations in North and South America that will be crucial for species movement in a changing climate. Large movements are expected in the southeastern US, the Amazon region, and parts of Brazil. Some of the areas where migration is expected have undamaged biological regions. Others, in particular the southeastern US and Brazil, have pathways that are heavily impacted by human activities, which may create a barrier to the migration routes.
In the study, the team of scientists first identified what they call “climatically suitable” conditions for each of the species under a changing climate situation. They plotted routes for the species from areas that were projected to be unsuitable to these suitable areas. The routes were plotted so that they avoided the most heavily human-impacted regions. They then plotted the paths on a map for easy visualization.
Some concrete and specific examples were provided. The authors have identified 14 biological regions and calculated the average direction of movement across each biome (生物群系). Great visualizations are shown of paths of migrations, for instance, in the southeastern US.
| Climate Change and Other Human Activities are Affecting Species Migration | |
| The | ● There is a ● Some animals will have to adapt to higher temperatures. Other animals have no |
| Climate change and land use change mainly | |
| ● ● Some species movement destinations in a changing climate are mainly ● 14 biological regions are detected and some ideal | |
| Process of the study | ● Scientists first find out “ climatically suitable ” conditions for each of the species. ● They then drew up routes for the species and plotted the paths on a map with the |
【推荐3】Thirty years ago, if you looked down from a plane at the east coast of Australia, you would be greeted by the breathtaking beauty of the Great Barrier Reef (大堡礁), the world's largest coral reef. It stretched for over 2,600 kilometres in the blue sea, containing countless corals and small islands. It was listed as a UNESCO World Heritage Site in 1981.
However, this natural wonder of the world is being taken away from us. Coral cover in the Great Barrier Reef has dropped by more than half over the last 28 years, The Guardian reported. “If the trend continues, coral cover could halve again by 2022,” said Peter Doherty, researcher at the Australian Institute of Marine Science (AIMS). So unless we start acting now, there won’t be any “heritage” left in the future.
Coral reefs are an important part of the ocean’s ecosystem. They are a source of food, and act as protection for young fish. But in the past three decades they have been under threat around the world mainly from increased storms, a growing number of crownofthorns starfish and coral bleaching (褪色).
Storm damage caused nearly half of the coral losses. In the past seven years, the reef has been affected by six major storms, each leaving a trail (痕迹) of destruction.
The crownofthorns starfish is also causing problems. Scientists believe that runoffs (地表径流) containing a large amount of fertilizers have caused the population boost of this coraleating animal. Outbreaks of crownofthorns starfish usually start two or three years after major floods in northern rivers.
Coral bleaching accounts for about 10 per cent of coral damage. It is usually due to ocean acidification (酸化) and rising temperatures because sea water absorbs more carbon dioxide from the air. This disrupts the corals' ability to grow and build structures.
The good news is that corals can recover if given the chance. But this is slow. And the future of the ocean’s coral is largely in human hands.
“We can’t stop the storms…But we can achieve better water quality, and we can deal with the challenge of crownofthorns starfish,” says John Gunn, CEO of AIMS. “However, its future also lies with the global response to reducing carbon dioxide emissions (排放). ”
1. What can we learn about the Great Barrier Reef from the article?| A．As the world’s second largest coral reef, the Great Barrier Reef was listed as a UNESCO World Heritage Site. |
| B．The Great Barrier Reef has lost more than half of its coral cover since 28 years ago. |
| C．At the present rate of loss, the coral cover will reduce by another 30 per cent within a decade. |
| D．Coral reefs are an important part of the ocean's ecosystem and can prevent ocean acidification. |
| A．at risk | B．out of sight |
| C．in demand | D．beyond recognition |
a. Improve water quality.
b. Reduce global carbon dioxide emissions.
c. Disrupt the coraleating starfish’s ability to build structures.
d. Control the population of the crownofthorns starfish.
e. Make ocean absorb more carbon dioxide from the air.
| A．a, b, c | B．a, b, d |
| C．a, c, e | D．b, d, e |
【推荐1】Researchers have claimed a major step forward in the field of organ transplantation after a monkey survived for more than two years with a genetically engineered pig kidney.
Scientists have spent decades working out whether animal organs could ever work properly and safely in humans without them being rejected by the patient’s immune system, but the challenges have proved immense.
For the latest trial, researchers used a gene-editing tool called Crispr to alter genes in Yucatan miniature pigs before transplanting their kidneys into macaques (猕猴). The modifications altered genes to prevent organ rejection and remove pig viruses that could potentially be activated in recipients.
Writing in the journal Nature, the scientists describe how 21 monkeys got on after their kidneys were removed and a single genetically modified pig kidney was implanted. Monkeys typically survived no more than 24 days when the kidneys were edited to disable three genes that triggered immune rejection. But when the scientists added seven human genes that reduce blood clotting (结块), inflammation and other immune reactions, the monkeys survived seven times longer, typically for 176 days. When combined with treatment to restrain the immune system, the researchers report that one monkey survived for more than two years — 758 days — with the transplanted organ.
Curtis, the chief executive of eGenesis, said the long-term survival of at least some of the monkeys had put eGenesis on course to satisfy the US Food and Drug Administration requirement to see at least 12 months’ survival in animals before the team can launch a clinical trial in humans. “We are well on our way there,” Curtis said. “There simply aren’t enough kidneys to go around. In our opinion it’s the only near-term practicable solution.”
The team uses Yucatan miniature pigs as donors because at maturity their kidneys are roughly the same size of those in the adult human. In the monkey trial, the kidneys were transplanted at two to three months when the organs were much smaller.
Prof Tatsuo Kawai, an author on the study at Harvard Medical School, said the scientists expected the modified pig organs to perform better in humans than monkeys because “they are a better match”.
1. What do researchers do with the Yucatan miniature pigs?| A．They altered their immune systems. | B．They changed their genes to prevent rejection. |
| C．They used them to produce a gene-editing tool. | D．They transplanted their kidneys into human beings. |
| A．The 21 monkeys were implanted with a healthy pig kidney. |
| B．The monkeys usually survived less than 24 days previously. |
| C．Researchers removed three genes causing immune rejections from the kidneys. |
| D．Monkeys can survive much longer if their genes are modified property. |
| A．Dissatisfied. | B．Doubtful. | C．Content. | D．Indifferent. |
| A．Monkey survives for over two years with a genetically engineered pig kidney. |
| B．A big breakthrough has been made in the field of organ transplantation. |
| C．Animal organs can work in an effective way in the bodies of human beings. |
| D．It’s high time to make some adjustments to human immune system. |
【推荐2】In the past 50 years, the amount of water in the open ocean with zero oxygen has gone up more than fourfold. In coastal water bodies，including river mouths and seas, low-oxygen sites have increased more than tenfold since 1950.Scientists expect oxygen to continue dropping even outside these zones as Earth warms .
“Oxygen is fundamental to life in the Oceans,” said Denise Breitburg, a marine ecologist with the Smithsonian Environmental Research Center. “The decline in ocean oxygen ranks among the most serious effects of human activities on the Earth ’s environment. Actually, it's a great loss to all the support services that rely on recreation and tourism, including hotels and restaurants and taxi drivers and everything else. The reverberations(严重影响) of unhealthy ecosystems in the ocean can be extensive.”
In areas traditionally called “dead zones" , like those in Chesapeake Bay and the Gulf of Mexico，oxygen plummets(大幅下跌) to so low levels that many animals die. As fish avoid these zones, their habitats become smaller and they’ re easier to be attacked or caught. But the problem goes far beyond “dead zones”. Even smaller oxygen decline can prevent growth in animals, hinder reproduction and lead to disease or even death. It also can cause the release of dangerous chemicals such as nitrous oxide, a greenhouse gas up to 300 times more powerful than carbon dioxide. While some animals can boom in “dead zones”，overall biodiversity falls.
Climate change is the key criminal in the open ocean. Warming surface waters make it harder for oxygen to reach the inside of the ocean. Furthermore, as the ocean as a whole gets warmer, it holds less oxygen. In coastal waters, too much nutrient pollution from land creates algal blooms, which use up oxygen as they die and break down.
People's livelihoods are also on the line, the scientists reported, especially in developing nations. Smaller fisheries(渔场)may be unable to relocate when low oxygen destroys their harvests or forces fish to move elsewhere. So we humans have to carry on a war now and win the war.
1. What does the first paragraph mainly talk about?| A．The ocean has been losing its oxygen. | B．The amount of sea water is increasing. |
| C．The coastal water bodies are dangerous. | D．The Earth becomes warmer and warmer. |
| A．Different oceans have different levels of oxygen. |
| B．The decline in ocean oxygen has great influences. |
| C．The future of tourism relies on the levels of ocean oxygen. |
| D．The decrease in ocean oxygen is the most serious environment problem. |
| A．It offers more food. | B．It forms dangerous gas. |
| C．It reduces their living areas. | D．It produces more carbon dioxide. |
| A．By closing smaller fisheries. | B．By controlling humans' bad activities. |
| C．By improving people's living standards. | D．By stopping nutrients entering the ocean. |
【推荐3】Researchers have recorded penguins making sounds underwater for the first time — the first time such behavior has been identified in seabirds. These animals, like other seabirds, are highly vocal on land. They are known to communicate when their heads are above the water in the ocean, possibly for the purposes of group formation.
However, until the latest study — published in the journal Zoological Science — it was not known whether penguins made sounds underwater, like some other air-breathing marine predators, such as whales and dolphins. For their research, a team of scientists led by Andréa from Nelson Mandela University in South Africa, wanted to investigate this issue. To do so, they fitted adult penguins from three species with video cameras featuring built-in microphones.
To the surprise of Andréa and her colleagues, the team recorded a total of 203 underwater vocalizations from the penguins in the underwater footage they captured over a month-long period in 2019. These are the first recordings of seabirds producing vocalizations underwater. “I couldn’t believe it. I had to replay it many times,” Andréa said.
The vocalizations that the team recorded — which sound like rapid whoops — were very short in duration, lasting about 0.06 seconds on average. And all of these sounds were emitted（发出）during dives in which the animals were searching for food. Currently, it is not clear why the penguins are making these sounds; however, they only produce them while hunting. In fact, more than 50 percent of the vocalizations were immediately preceded by an acceleration movement or followed by an attempt to hunt.
According to the researchers, this suggests that the sounds are related to hunting behavior — especially because the penguins tend to be alone when they make them, indicating that communication was not the purpose. The researchers guess that the penguins may be using the vocalizations to stun(使昏迷) their prey. However, much more research is required to determine why the penguins make these sounds, the scientists note.
1. How does Andréa’s team conduct the study about penguins?| A．By recording penguins’ sounds on land. |
| B．By fixing electronic devices on the penguins. |
| C．By observing penguins’ activities underwater. |
| D．By catching different kinds of adult penguins. |
| A．Penguins’ sounds are too low to hear. |
| B．She doubts if penguins could make sounds. |
| C．Penguins seldom make sounds underwater. |
| D．It’s not easy to obtain penguins’ sounds underwater. |
| A．When they take a deep breath. |
| B．When they dive to hunt for food. |
| C．When they teach their babies diving. |
| D．When they communicate with their partners. |
| A．Cautious. | B．Negative. |
| C．Supportive. | D．Indifferent. |
【推荐1】On a freezing January morning Jonny Benjamin, then a 20-year-old college student, climbed on the edge of Waterloo Bridge in London. That morning, Jonny escaped from a mental health hospital, where he’d been diagnosed (诊断) with schizo-affective disorder. He headed straight to the bridge, convinced that his disease was a life sentence.
Hundreds of people passed by. Only one man called Neil Lay bourn, then 25, calmly and quietly walked to Jonny’s side.
“You’re alright, man? Why are you sitting on a bridge?”
At first Jonny wanted Neil to leave him alone, but something in Neil’s calm, down-to-earth manner struck a chord. Jonny felt faith, like he could talk to him.
“It’s cold here. Why not have some coffee in a warm cafe? Everything will be OK.” For the first time after the diagnosis Jonny Celt perhaps it really might. He climbed back.
The police, having received calls from passers-by, were waiting there. They quickly put him into a police car, in case he was to panic and jump. He lost sight of Neil, the person who’d brought him hope.
Jonny ended up back in hospital. Eventually, he was well enough to return to university and finish his degree. Over the next six years, Jonny often thought about the stranger who had talked him round. Eager to thank him in person, he posted a Facebook message nicknaming the good man Mike. His #Find-Mike post was shared millions of times around the world, as far as Canada.
Jonny was overexcited when Neil called him two weeks after his post. They had a reunion, finally having that coffee they had first planned all those years ago.
“Many people walked past, but because of Neil’s kindness and sympathy, I’ve lived a good life.” Jonny said.
1. Why did Jonny climb up the bridge?| A．He was badly treated in the hospital. | B．His disease made him lose hope. |
| C．He wanted to draw people’s attention. | D．He studied poorly in the college. |
| A．Touched his heart. | B．Drew his attention. |
| C．Aroused his interest. | D．Blew his mind. |
| A．Humorous. | B．Tough. | C．Kind. | D．Generous. |
| A．By asking the police. | B．By calling their friends. |
| C．By posting a message online. | D．By visiting homes door-to-door. |
【推荐2】
Pesticides might just be a bee's worst enemy. They harm their brains, slow down their reproduction, and even kill their buzz. Now it seems they damage their social lives and reduce their ability to care for their young.
While previous studies have shown that commonly used neonicotinoid（新烟碱类）pesticides make bees sick and affect how they search for food and navigate, a new study gives more of an idea of how these chemicals affect the internal workings of a colony（种群）. Studying these effects has proved difficult, so the team employed a new technique. They stuck tiny QR codes to the backs of humblebees and tracked their movements using a robotic camera.
The researchers looked at 12 colonies housed in a lab, giving some the same level of imidacloprid—the world's most commonly used pesticide—that they'd be exposed to in the wild while keeping others pesticide-free as controls. They checked on them for a few minutes 12 times a day. The findings are published in the journal Science.
Unfortunately, the researchers found a number of obvious differences between the bees exposed to the pesticide and the controls. The bees given neonicotinoids spent less time interacting with other bees and more time resting. This pause in activity tended to happen more at night, but the researchers aren't sure why.
"Bees actually have a very strong circadian rhythm（生理节奏）," lead author James Crall explained in a statement. "So what we found was that, during the day, there was no statistically observable effect, but at night, we could see that they were crashing. We don't know yet whether the pesticides are destroying circadian gene regulation or if this is just some, maybe physiological feedback…But it suggests that, just from a practical perspective, if we want to understand or study these compounds, looking at effects overnight matters a lot."
1. What does the new study suggest about pesticides' effect on bees?| A．Pesticides lead to their disease. |
| B．Pesticides slow down their brain function |
| C．Pesticides upset their community. |
| D．Pesticides damage bees' internal parts. |
| A．The tools used to observe the bees. |
| B．The data recorded by the robotic camera |
| C．The researchers conducting the experiments. |
| D．The bees kept free from the pesticides. |
| A．The circadian rhythm of bees is stronger during the day. |
| B．It is vital to study the performance of bees at night |
| C．It is certain that pesticides affect bees only at night. |
| D．The pesticides do great harm to circadian gene regulation of bees. |
| A．To inform people of the worrying effects of pesticides. |
| B．To check the best time to observe experimental results. |
| C．To call for the toughest ban on the chemicals. |
| D．To recommend measures to improve the quality of pesticides. |
【推荐3】Worries about the extra time needed to walk or bike to work are a big reason people get into their cars, but those worries may be unfounded.
In a new study, researchers asked 253 staff and 252 students at Penn State how often they drove, took the bus, walked, or biked to school. Participants also answered questions about how long they thought it would take them to walk or bike from their home to school. Google Maps calculated actual travel times.
According to the findings, about 91 percent of staff incorrectly estimated (估计) how long it would take to walk to school, and about 93 percent overestimated how long it would lake to bike.
Students were a little better at estimating travel times－about 55 percent incorrectly estimated walking times and about 43 percent misestimated biking times. Almost everyone who was not accurate overestimated the travel time.
The findings clarify the barriers that keep people from walking or biking, sometimes referred to as“active travel,” says Melissa Bopp, a professor at Penn State. He pointed out the key to getting people to travel more actively is to learn more about people’ s knowledge, altitudes, and beliefs.“I can’ t change your age, but I can change your knowledge,”Bopp says.
Several characteristics could predict if someone was more likely to estimate travel time incorrectly. Staff who thought parking was more available and accessible were more discordant （不一致的), and women were more likely to be more discordant than men.
On the contrary, people who rode a bike or walked more often were more likely to accurately predict travel times.
While the study looked at people predicting travel time when they shared a common destination, the results have broader meanings.
1. Which of the following can best replace the underlined word “unfounded” in Paragraph 1?| A．unnecessary. | B．normal. |
| C．disturbing. | D．beneficial. |
| A．School staff lack common sense. |
| B．Everyone overestimated the traveling time by bike. |
| C．School students estimated more accurately in the study. |
| D．Students have higher intelligence than school staff. |
| A．Weight. | B．Status. |
| C．Age. | D．Knowledge. |
| A．Walking or biking is beneficial to you. |
| B．Walking or biking is quicker than you’ d think. |
| C．Walking or biking is becoming more popular. |
| D．People walking or biking can predict accurately. |
【推荐1】Procrastinators (拖延症患者)，take note: If you’ve tried building self-control and you’re still putting things off, maybe you need to try something different. One new approach: Check your mood.
Often, procrastinators attempt to avoid the anxiety or worry aroused by a tough task with activities aimed at repairing their mood, such as checking Facebook or taking a nap. But the pattern, which researchers call “giving in to feel good,” makes procrastinators feel worse later, when they face the consequences of missing a deadline or making a last-minute effort, says Timothy Pychyl, an associate professor of psychology at Carleton University.
Increasingly, psychologists and time-management consultants are focusing on a new strategy: helping procrastinators see how attempts at mood repair are destroying their efforts and learn to control their emotions in more productive ways.
The new approach is based on several studies in the past two years showing that negative emotions can damage attempts at self-control. It fills a gap among established time-management methods, which stress behavioral changes such as adopting a new organizing system or doing exercises to build willpower.
Researchers have come up with a playbook of strategies to help procrastinators turn mood repair to their advantage. Some are tried-and-true classics: Dr. Pychyl advises procrastinators to just get started, and make the doorstep for getting started quite low. “Procrastinators are more likely to put the technique to use when they understand how mood repair works,” says Dr. Pychyl, author of a 2013 book, “Solving the Procrastination Puzzle.” He adds,“A real motive power comes from doing what we intend to do—the things that are important to us.”
He also advises procrastinators to practice “time travel”—projecting themselves into the future to imagine the good feelings they will have after finishing a task, or the bad ones they will have if they don’t. This cures procrastinators’ tendency to get so stuck in present anxieties and worries that they fail to think about the future.
Another mood-repair strategy, self-forgiveness, is aimed at dismissing the self-blame. University freshmen who forgave themselves for procrastinating on studying for the first exam in a course procrastinated less on the next exam, according to a recent study led by Michael Wohl, an associate professor of psychology at Carleton.
Thomas Flint learned about the technique by reading research on self-control, including studies by Dr. Sirois and Dr. Pychyl. He put it to use after his family moved recently to a new house. Instead of beating himself up for failing to unpack all the boxes gathered in his garage right away, Mr. Flint decided to forgive himself and start with a single step. I’d say, "OK, I’m going to take an hour, with a goal of getting the TV set up, and that's it, he says; then he watched a TV show as a reward. Allowing himself to do the task in stages, he says, is “a victory.”
1. What does Timothy Pychyl mean by mentioning the “giving in to feel good” practice in Paragraph 2?| A．It probably does more harm than good. |
| B．It prevents procrastinators from giving up. |
| C．It helps procrastinators meet the deadline. |
| D．It effectively drives away anxiety and worry. |
| A．Sticking to one’s intention. |
| B．Doing things that really matter. |
| C．Getting started from a low doorstep. |
| D．Learning important techniques of mood repair. |
| A．To make their future plan more practical. |
| B．To accelerate the speed of finishing the task. |
| C．To stop people from worrying about their travel. |
| D．To free people from the present negative emotions. |
| A．Self-blame prevents students from putting things off. |
| B．Procrastinators are still able to get good scores in exams. |
| C．University freshmen can get rid of procrastination easily. |
| D．Self-forgiveness is an effective way to cure procrastination. |
【推荐2】Hibernation
For people who aren’t fans of winter, animals that hibernate seem to have the right idea: It’s the equivalent of burying your head under the covers until spring comes — isn't it? Not quite.
“Most of the physiological functions are extremely slowed down,” says Marina Blanco, a postdoctoral associate at the Duke Lemur (狐猴) Center in Durham, North Carolina. For example, when lemurs hibernate, they reduce their heart rates from over 300 beats per minute to fewer than six, says Blanco. And instead of breathing about every second, they can go up to 10 minutes without taking a breath. Their brain activity “becomes undetectable.” This is very different from sleep, which is gentle resting state where unconscious functions are still performed.
Put simply: “Hibernation is a means of energy conservation,” says Kelly Drew, a neuropharmacologist at the University of Alaska Fairbanks who studies the brain chemistry of hibernating Arctic ground squirrels.While hibernation is often seen as a seasonal behavior, it’s not limited to cold-weather animals. There are tropical hibernators that may do so to beat the heat. And “some species hibernate in response to food shortages,” notes Drew. For example, echidnas ( 针 鼹 ) in Australia will hibernate after fires, waiting until food resources rebound to resume normal activities.
To slow their metabolism (新陈代谢), animals cool their bodies by 5 to 10 °C on average. The Arctic ground squirrels Drew works on can take this much further, supercooling to subfreezing temperatures. Drew’s research has shown that cooling is likely regulated by levels of adenosine (腺苷) in the brain. Not only does adenosine increase in winter in ground squirrels, the receptors for the molecule become more sensitive to it.
But species don’t stay in their cold, sleeping state for the duration of their dormant period. About 80 percent of their energy is spent intermittently (间歇地) waking and warming up. Why they do this is “one of the greatest mysteries” of the field, says Thomas Ruf, a professor of animal physiology at the University of Veterinary Medicine in Vienna. Some think they need to turn back on their immune systems to fight disease, while others think they may simply awaken so they can sleep.
One bird and a variety of amphibians(两栖动物), reptiles and insects also exhibit hibernation-like states. There is even at least one fish — the Antarctic cod — that slows down its metabolism in winter, becoming 20 times less active. And, of course, there are lots of mammals. While bears might be the first that come to mind, most mammalian hibernators are on the smaller side. “The average hibernator weighs only 70 grams,” says Ruf. That’s because little bodies have high surface area to volume ratios, making it more taxing for them to stay warm in cold weather — so they need the seasonal energy savings more than larger animals.
1. How does the author distinguish between hibernation and sleep?| A．By highlighting reasons. | B．By presenting definitions. |
| C．By introducing arguments. | D．By comparing the data. |
| A．animals cool their bodies by 5 to 10°C on average |
| B．tropical hibernators may hibernate to beat the heat |
| C．some species hibernate in response to food shortage |
| D．hibernation is most often seen as a seasonal behavior |
| A．when certain animals hibernate | B．what kinds of animals hibernate |
| C．why some animals hibernate | D．how animals hibernate |
| A．It is harder for smaller animals to keep warm in winter. |
| B．The cooling of bodies may influence the levels of adenosine. |
| C．Scientists don’t agree on the reasons of intermittent hibernation. |
| D．Body functions are still unconsciously performed during hibernation. |
【推荐3】Just like any other home, the International Space Station (ISS) requires some housekeeping in the form of routine work and repairs That is why NASA astronaut Scott Kelly and fellow astronaut Kjell Lindgren performed a spacewalk outside the station on Wednesday. The operation began at 8:03 a.m. and lasted for more than seven hours. It was the first spacewalk for both men.
The ISS has been in constant use for 15 years and needs to be upgraded (升级) from time to time. During their spacewalk, Kelly and Lindgren did basic electrical work, such as attaching new cables that will provide power to docking ports on the station. The ports will be used when new crew (工作人员) and cargo ships arrive at the ISS in 2017. The two astronauts also placed a thermal (防寒的) cover on a key scientific instrument on the station to protect it from the cold temperatures of space.
As the more senior astronaut, Kelly led the spacewalk. However, Lindgren handled some of the more challenging parts of the job in some of the tighter areas of the station.
“Lindgren has longer arms,” said NASA'S Grant Slusser, who served as ground director for Wednesday's spacewalk.
Kelly and Lindgren spent months training and practicing for the operation. The preparation began in NASA's Neutral Buoyancy Lab (NBL), a 6.2-million-gallon swimming pool with a full-size replica (复制品) of most of the ISS located at the bottom. Here astronauts become accustomed to working in an environment similar to the one outside the space station.
During the spacewalk, Kelly and Lindgren received updates from NASA that provided them with both major and minor detail, right down to how many turns are needed to tighten a bolt (螺栓).
Once the task was successfully completed, the astronauts reentered the ISS. But they will not remain inside the station for too long. Both men will perform a second spacewalk scheduled for November 6.
1. What is Paragraph 2 mainly about?| A．The goal of Wednesday's spacewalk. |
| B．The duties of NASA astronauts in space. |
| C．The role of the International Space Station. |
| D．The flight schedules of spaceships in 2017. |
| A．He is several years senior to Kelly. |
| B．He has a physical advantage over Kelly. |
| C．He has more work experience than Kelly. |
| D．He is braver and more confident than Kelly. |
| A．started at night. | B．seemed a difficult task. |
| C．was directed by the NBL. | D．was their second spacewalk. |
| A．Go back to the earth. |
| B．Welcome the new crew's arrival. |
| C．Prepare for their next spacewalk. |
| D．Get in touch with the ground control center. |
