【推荐2】A team of researchers at Harvard University and Emory University have created a school of robotic fish. They can swim by recreating the contractions (收缩) of a pumping heart. Researchers say the experiment could advance pacemaker (心脏起搏器) technology and improve the development of artificial hearts for humans.

Researchers built the zebrafish-based fish using paper, gelatin (明胶), plastic fin, and two layers of human heart muscle cells. One ran along the robot’s left side, while the other along the right. When the muscle cells on one side contracted, the tail moved in that direction. This allowed the fish to swim in the water. The opposite side’s muscle cell layer similarly stretched as a result of the action. This stretching then sent a signal to the cells, causing them to contract, which kept the swimming motion going. The researchers also created an autonomous pacing node (节点), similar to a pacemaker, which controls the frequency and rhythm of these contractions.

The fish moved autonomously for over 108 days, equal to 38 million beats, the study stated. “Because heart cells constantly rebuild themselves, which takes about 20 days, the fish cells rebuild themselves about five times,” says Kit Parker, a professor from Harvard University who led the research. The fish eventually reached speeds and swimming efficiency comparable to wild zebrafish.

“Though the researchers say the fish is a step forward for heart research, it could be years before it leads to the creation of an artificial heart,” says Michael Schneider, a professor at Imperial College London, who wasn’t involved in the study. But that doesn’t dishearten Parker. “I think other methods will be faster than us,” says Parker. “But in the long run, creating tissue that relies on the patient’s own cells could offer unexpected benefits.”

1. What does Paragraph 2 mainly tell us?

A．Why the robotic fish was created.	B．What enabled the robotic fish to swim.
C．Who got involved in the experiment.	D．How fast the robotic fish could swim.

2. Which is true about the robotic fish according to Paragraph 3?

A．They were rebuilt by human doctors.

B．They didn’t move as Parker expected.

C．They finally swam as fast as wild zebrafish.

D．They grew into the size of wild zebrafish.

3. What does the underlined word “dishearten” mean in the last paragraph?

A．Discourage.

B．Surprise.

C．Amuse.

D．Relieve.

4. What can we learn from the text?

A．The findings may aid in heart research.

B．The first artificial hearts have been created.

C．Parker got no support from other scientists.

D．The researchers were upset about the findings.

【推荐2】The great Swiss psychologist Jean used to lecture around the world, explaining how children’s minds develop as they get older. Once an American asked, “But Prof. Jean, how can we get them to do faster?” Today it’s no longer just impatient Americans who assume that faster brain and cognitive (认知的) development is better. Across the globe, both parents and policy makers eagerly push preschools to be more like schools.

A wave of new research shows, however, that this picture is far too simple. In 1998 a landmark series of studies looked at the long term effect of Adverse Childhood Experiences (ACEs) on children’s growing up. ACEs include physical or emotional overlook or abuse, being poor, losing parent, violence or mental (精神的) illness in the home. Since the original studies, there have been hundreds of similar ones done across the world. It turns out that ACEs are disastrously common.

A new paper by Dr. Mackey, published in Nature Neuroscience Reviews, also concludes that. ACEs seem to make children’s brains grow up too quickly. Dr. Mackey suggests that frequently repeated bad experiences may have the worst speeding up effect, while more varied and unusual good experiences may be particularly likely to keep the brain open to learning.

Why would stress and disasters make us grow up faster and a rich, varied, nursing environment make us grow up more slowly? One influential recent idea takes off from the biological concept of “life history”. An animal’s life history includes how long it lives, how much it invests in its young and how long it takes those young to mature. A “live fast, die young” life history makes more developmental sense when resources are few and life is predictably hard.

In brief, a long, slow life history goes with a big, smart brain. All of this should be able to relieve the parents’ worries about “the American question”. Loving your children and giving them space to learn and explore is more important than designing a particular curriculum (课程).

1. What can we infer from paragraph 1?

A．Americans are usually smarter than others.

B．American brain science is better developed.

C．Most people believed children should skip preschools.

D．Most people wish to develop their children’s brains faster.

2. What is Dr. Mackey’ s opinion about speeding up children’s brain?

A．It leads to an early death.

B．It may cause painful problems.

C．It is beneficial to academic learning.

D．It originates from unpleasant environment.

3. What does the author finally advise parents to do?

A．Push preschools to be more like schools.

B．Put middle-high pressure on their children.

C．Give children care and freedom to learn and explore.

D．Ask teachers to design abundant curricula for children.

4. What may be the best title for the text?

A．Live Fast, Die Young

B．Faster Development, Better Future

C．An American Question, the World’s Problem

D．ACEs, Key to Children’s Brains’ Development

【推荐3】Are you curious about mysterious creatures? We are going to tell you about some here.

Okapi

If giraffes and zebras could produce a next generation, their babies would look like an okapi. This strange-looking creature has striped legs like a zebra and the face of a giraffe. Its neck is much shorter than a giraffe, but like its cousin, it has an extremely long tongue, which can be up to 12 inches long. The okapi can use its tongue to wash its own eyelids and ears. Before 1901, Okapis were known only to the people living in the Congo rainforest.

Loch Ness Monster

The locals near Loch Ness in northwestern Scotland refer to the mysterious creature as "Nessie". Nessie is said to be a large animal with a long neck that lived during the time of the dinosaurs. Similar creatures have been reported in other lakes around the world. But whether it is real remains unknown.

Ivory-Billed Woodpecker

By the mid-1990s, the ivory- billed woodpecker was widely believed to have died out due to deforestation(砍伐森林) and hunting. It was rediscovered in 2004, when a bird lover reported seeing one alive in the woods of Arkansas, America. Researchers later got a video of the bird.

King Cheetah

Starting in 1926, people in Zimbabwe began to see a cheetah with unusual markings. This cheetah has large spots like a leopard(美洲豹) and black stripes down its back. People called the creature "king cheetah". It is a leopard-cheetah hybrid (混合).

1. Which of the following is TRUE about the okapi?

A．It is produced by a giraffe and a zebra.

B．It was not widely known until the twentieth century.

C．Its neck is much shorter than that of a zebra.

D．It was first found in 1901.

2. What can we learn from the passage?

A．People still don’t know why the king cheetah has strange markings.

B．The giraffe has a short tongue.

C．Nessie is a kind of dinosaur.

D．The decrease in forests has had a great effect on the ivory-billed woodpecker.

3. Where can one most probably find this passage?

A．In a nature magazine.	B．In a travel guide.
C．In a book of fairy tales.	D．In an advertisement.

【推荐1】By 2050, 68% of the global population will live in cities. That’s 2.5 billion more people than today. In Europe, three out of four of us already live in urban areas, and the consequences of that are becoming clear. Researchers estimate that nine million people die every year as a direct result of air pollution. As our cities grow and more people move into already crowded spaces, what do we need to do to transform our urban areas into healthy places to live? An increasing body of research tells us that we should be letting nature back in.

Green spaces in cities mitigate the effects of pollution and can reduce a phenomenon known as the urban heat island effect, which refers to heat trapped in built-up areas. The effect appears in towns and cities where the heat generated by people, transport and industry is trapped in the narrow roads and concrete structures, unable to escape to the atmosphere. This can bring the temperature in urban areas up 3 — 4°C higher than the surrounding countryside, and with that comes a severe cycle. Increased temperatures in summer lead to an increased demand for cooling. This expands our energy consumption, which in turn build up fossil fuel consumption, increasing pollutants in the air and harmful smog on our streets.

Planning cities to include green spaces wherever possible is the first step in making our urban areas healthier. For example, adding a layer of vegetation to rooftops and creating green roofs has proven to reduce the urban heat island effect. Trees in our streets also play their part, and a variety of tree species can have a profound effect. Simply having access to green spaces in cities can do wonders for our stress levels and concentration at work. “People need to interact with nature whenever the opportunity arises. Something as simple as a five-to-ten-minute break during the workday can improve well-being and boost productivity,” Cecil, an expert studying nature in cities says.

1. How does the author bring in the topic in Paragraph 1?

A．By presenting facts.	B．By listing examples.
C．By comparing numbers.	D．By questioning an estimate.

2. What does the underlined word “mitigate” mean in Paragraph 2?

A．Overcome.

B．Change.

C．Ease.

D．Shift.

3. What might be a consequence of the urban heat island effect?

A．Lower temperature.	B．Energy regeneration.
C．Fuel shortage.	D．Air pollution.

4. Which of the following can be the best title for the text?

A．How to Let Nature Back In

B．Why We Need Green Spaces in Cities

C．Heat Effect: An Unavoidable Urban Trouble

D．Green Roofs: Tiny Urban Forests

【推荐3】The Arctic Could be Practically “ice-free”

The Arctic could have summer days with practically no sea ice within the next decade due to emissions (排放) from fossil fuels (化石燃料), a study has found.

This would transform the unique habitat, home to polar bears, seals and walruses, from a “white Arctic” to a “blue Arctic” during the summer months, scientists said.

The report defined (定义) “ice-free” as less than 1m sq km of ice, in which case the Arctic Ocean would be mostly water.

The findings, published in the journal Nature Reviews Earth & Environment, suggest the first ice-free day in the Arctic could occur more than 10 years earlier than previously predicted.

The authors said continuously ice-free Septembers could be expected by 2035 to 2067, depending on fossil fuel emissions. By the end of the century, there was potential for ice-free conditions between May and January under a high-emission scenario (可能发生的情况), and August to October under a low-emission scenario.

Alexandra Jahn, a lead author of the research, said: “This would transform the Arctic into a completely different environment. But even if ice-free conditions are unavoidable, we still need to keep our emissions as low as possible to avoid prolonged (长期的) ice-free conditions.”

There was, however, potential to fix this issue, she said. “Unlike the ice sheet in Greenland that took thousands of years to build, even if we melt all the Arctic sea ice, if we can then figure out how to take CO₂ back out of the atmosphere in the future to reverse (逆转) warming, sea ice will come back within a decade,” Jahn said.

1. According to the study, when could the Arctic experience its first ice-free summer day?

A．By the end of this decade.	B．Within the next 10 years.
C．From 2035 to 2067.	D．By the end of the century.

2. What would happen if the Arctic became ice-free during summer months?

A．The Arctic habitat would remain unchanged.

B．The Arctic would still be friendly to polar animals.

C．The Arctic would be a “blue Arctic” in summer.

D．The Arctic would remain frozen throughout the year.

3. What would Alexandra Jahn probably agree with?

A．Ice-free conditions are avoidable.

B．The Arctic would under go no transformation.

C．Emissions ought to be reduced.

D．Prolonged ice-free conditions are certain to occur.

4. How does Alexandra Jahn feel about dealing with the Arctic warming?

A．Hopeful.

B．Indifferent.

C．Pessimistic.

D．Uninterested.