1 . The Arctic's permafrost is inciting— and fast. That's bad news, because these frozen soils store billions of tons of carbon, just waiting to be released. So is there a way to save the permafrost? One team of researchers thinks it may have found a possible solution: big animals, herbivores - animals that eat only plants.
Back in 1996 researchers started an experiment called Pleistocene Park. They fenced in about eight square miles of land in northeast Siberia. Then they introduced different types of herbivores: reindeer, horses, bison, sheep and other large creatures.
Since then, scientists have studied these animals' effects on the ecosystem. One outcome is that these large herbivores help keep the ground very cold — cooler than it would otherwise be.
“The snow in winter is important for soil temperature, because it acts as an insulating layer. So the air in winter, at the high latitudes, is much colder than the soil." Philipp Porada, a vegetation ecologist at the University of Hamburg. "So the idea of this experiment was to introduce large herbivores — and to quantify their effects on soil temperature to see if they can actually protect permafrost soils against melting. And this works because of the animals' trampling (践踏), and this leads to less insulation of the soil against cold air temperatures and results in a cooling effect.”
Freezing air reaches the soil more easily. Porada and his colleagues realized the significance of this effect, so they pulled data from Pleistocene Park and Sweden to model what effect herbivores could have on permafrost if they lived in large numbers in the Arctic.
They found that even in a worst-case situation, some four degrees Celsius of global wanning: “These herbivores in the model reduce soil temperature substantially, by 1.7 degrees on average. And this leads to a preservation of around 80 percent of the original — today's permafrost area. Without the herbivore effect in the model, only 50 percent of the permafrost area would remain by the year 2100. So we can say the effect of the herbivores in the model leads to a substantial preservation of permafrost soil."
1. Why is the Pleistocene Park Experiment mentioned?| A．To provide the past research data. |
| B．To share soil preservation experience. |
| C．To introduce a way to save permafrost. |
| D．To prove animals' effect on soil temperature. |
| A．Covering. | B．Blocking. |
| C．Storing. | D．Freezing. |
| A．Cooling the ground. | B．Heating the soil |
| C．Damaging the ground. | D．Softening the soil. |
| A．Permafrost Is Disappearing | B．Preservation of Permafrost |
| C．An Experiment on Herbivores | D．Herbivores Help Save Permafrost |
2 . If you've ever watched Planet Earth, you know the ocean is a wild place to live. The water is full of different ecosystems and organisms varying in complexity from an erudite octopus to a sea star. Unexpectedly, it is the sea star, a simple organism characterized by a decentralized (分散的) nervous system, that offers insights into advanced adaptation to hydrodynamic forces — the forces created by water pressure and flow.
Researchers found that sea stars effectively stay attached to surfaces under extreme hydrodynamic loads by altering their shape. Sea stars create a "downforce" due to their shape. This mean that instead of being lifted by the flow forces, the sea stars are pushed downward toward the rock or floor surface they are on.
"Sea stars are incredibly adaptive," said Luhar, assistant professor. “When there is high wave activity and high water forces, sea stars will grow skinnier and take on a lower profile (姿态). When the sea star is transported to a sheltered environment with lower hydrodynamic forces, they pop up a bit and their cross sections get bigger."
Understanding such shape shifting could help design underwater robots that can similarly adapt to extreme hydrodynamic environments, Luhar said.
The researchers tested this understanding of sea star shape and its impact on force in the water with both computational and 3-D printed models. “Right away what we noticed," Luhar said, "is that instead of the sea stars being pulled away from the surfaces they were on, they were being pushed down- simply because of their shape."
Luhar said the researchers saw this downforce effect as key to how the sea star- and in the future, an underwater robot could stay attched to a sea bed or a rock as opposed to being lifted up away from it, even in the most extreme conditions.
1. According to the first paragraph, what impresses us most about a sea star?| A．Its simple organism. | B．Its great adaptation. |
| C．Its nervous system. | D．Is physical appearance. |
| A．By creating upward force. | B．By shifting its shape. |
| C．By lifting itself upward. | D．By expanding its size. |
| A．We can develop 3-D printed models. |
| B．We can attach sea stars to the sea bed. |
| C．We can make technological advances. |
| D．We can change the extreme conditions. |
| A．Can we make a robot adaptive underwater? |
| B．Are sea stars incredibly advanced creatures? |
| C．Are scientists able to design underwater robot? |
| D．Can we transform sea stars' shape very flexibly? |
3 . A century ago, people needed help to understand science. Much as they do today.
Then as now, it wasn't always easy to sort the accurate from the erroneous. Media regarded science as secondary to other mission. When science made the news, it was often confusing, or misleading.
E.W. Scripps, a newspaper publisher, and William Emerson Ritter, a biologist, sensed a need for reliable news about science, devoted to truth and precision. So Science Service was born - soon to give birth to the magazine now known as Science News.
In its first year, Science Service delivered its weekly news reports to newspapers. By 1922 they became available to the public, giving birth to Science News-Letter, the ancestor of Science News. Then as now, the magazine included all flavors of science — from the atom (原子) to outer space, from agriculture to oceanography, from transportation to nutrition.
In those early days, much of Science Service focused on space and new technologies, filled with various guessing and arguments. Much of the century's scientific future was predicted, though not all predictions aged well.
In the century since, real science has progressed to an advanced degree of wisdom, to an extent almost unimaginable to the scientists and journalists of the 1920s.
When Science Service launched its mission, astronomers were unaware of the extent of the universe. No biologist knew what DNA did. Geologists saw that Earth's continents looked like separated puzzle pieces, but declared that to be a coincidence.
Modern scientists know better. Yet somehow scientists still pursue the same questions. It turns out that the past century's groundbreaking experimental discoveries, revolutionary theoretical revelations and prescient guessing have not removed science's familiarity with false starts, unfortunate missteps and shortsighted prejudices. Researchers today have expanded the range of the reality they can explore, yet still trip through the remaining uncharted jungles of nature's facts and laws, seeking further clues to how the world works.
Science is more like it is today than it ever has been. It remains as challenging as ever to human inquiry. And the need to communicate its progress, sensed by Scripps and Ritter a century ago, remains as essential now as then.
1. What led to the birth of Science Service?| A．Media's attitude to science. |
| B．Difficulty in defining science. |
| C．People's love for their mission. |
| D．Need for true and precise science. |
| A．The content of Science Service. |
| B．The future of Science Service. |
| C．The limits to the then scientists. |
| D．The problems facing modern scientists. |
| A．Uncaring. | B．Unfavorable. | C．Supportive. | D．Passionate. |
| A．Science in the past was not real science at all. |
| B．People have fully grasped the nature of science. |
| C．Today is the best time for science development. |
| D．Dependable news about science should be accessible anytime. |
4 . In recent years, Ethiopia has become a regional leader in solid waste management. Last year, the country transformed the landfill (垃圾填埋场) in Addis Ababa into a new waste-to-energy plant, the first such project on the continent. The plant incinerates up to 1, 400 tonnes of waste every day, about 80 percent of the city's rubbish, supplying the capital with 25 percent of its household electricity needs.
However, despite these important steps, challenges remain in Ethiopia. Although the country has permitted the Basel, Stockholm and Rotterdam conventions, laws and policies for environmentally sound management of hazardous (有害的) wastes are still not effective in pre- venting littering waste illegally.
To help Ethiopia meet these challenges, the Chemicals and Waste Management Program is supporting the country with a three-year project to enhance its capacity for sound management of hazardous wastes.
In the initial stages, a project management unit will be formed, made up of many representatives from government departments and private organizations. This unit will be responsible for reviewing and assessing Ethiopia's current legal system, which, despite numerous advances in recent years, does not specifically target the recycling of hazardous waste. Once legal gaps are identified, the project will seek to update existing policies and strategies.
Many people in Ethiopia are not aware of the possible effect of environmental damage and the need to report such crimes to the police. To resolve this pressing issue, Ethiopia will be conducting a series of capacity-building activities, including creating awareness-raising programs, training trainers and providing equipment.
Ethiopia will also work to establish a national mechanism for chemicals and waste management by engaging government departments and civil society groups. Authorities will also make budgetary provisions (预算拨款) in national, regional and institutional planning to ensure funding for these activities is sustainable even after the project's completion.
1. Which can replace the underlined word “incinerates” in paragraph 1?| A．Produces. | B．Burns. | C．Gathers. | D．Absorbs. |
| A．The relevant laws are not sound. | B．The shortage of workers is severe. |
| C．The pollution level is too high. | D．The funds are not sufficient. |
| A．Restrict their environmental movement. | B．Call on them to start some programs. |
| C．Reward them with budgetary provisions. | D．Raise their environmental awareness. |
| A．Ethiopia is facing serious environmental problems. |
| B．Ethiopia has achieved success in waste management. |
| C．Ethiopia is putting efforts into waste management. |
| D．Ethiopia has reduced environmental pollution levels. |
5 . Ian McKenna was in third grade when he learned that many kids at his Austin school weren't getting enough to eat at home. He wanted to help, but local volunteer organizations turned him away, saying he was too young. So he decided to find his own solution. For years, he had been gardening with his mother, and they often distributed their extra vegetables to the neighbors. “Why not give the produce to a soup kitchen? Then I thought, I'm good at gardening," says McKenna, now 16. “Why not plant a garden at school, so that kids in need could take food home?"
McKenna persuaded his school to set aside space for a garden; then he asked the community for donations of seeds and equipment. Other students donated their time. Within months, McKenna's garden was producing lettuces, tomatoes, cucumbers and squash for students and their families. Now, seven years later, McKenna's Giving Garden project has expanded to five area schools in addition to his own backyard garden, and he has provided organic produce, enough for 25,000 meals, to Austin families.
For most of his gardening activities, McKenna wears the same T-shirt in different colors, with his personal motto on it: BE A GOOD HUMAN. To him, that means helping in any way you can, no matter what your age. "Even a smile might change someone's life," he says. “It lets them know that they are important. It can make their day."
When COVID-19 hit the U.S., McKenna redoubled his efforts, cooking up to 100 meals to distribute to the hungry on the weekends. When social distancing meant that volunteers couldn't work on community garden plots, he started offering online classes and a gardening hotline so families could grow at home. While gardening is his core focus, McKenna says he is always looking for new ways to help the hungry.
1. What caused Ian's decision to help the kids in his own way?| A．Being rejected by volunteer groups. | B．Being good at gardening. |
| C．A soup kitchen's support. | D．His mother's suggestions. |
| A．It helps students only. | B．It was started with joint efforts. |
| C．It is funded by schools. | D．It earns great profits every year. |
| A．Where there is a will, there is a way. | B．A small gesture makes a difference. |
| C．One good turn deserves another. | D．Love can break all the barriers. |
| A．Ian McKenna, Growing a Food Bank |
| B．Ian Mckenna, an Experienced Gardener |
| C．Giving Garden Project, an Impossible Mission |
| D．Giving Garden Project, a Universal Solution |
6 . Here on Earth where most of us live, we spend about a third of everyday lying down sleeping and two-thirds standing or sitting in an upright position.
That's not really how it goes in space when people are weightless and the zero gravity environment causes more liquid to shift to the head. Faces get swollen, legs lose volume and appear to be smaller. Many astronauts have complained of eye and back problems after coming back down to Earth and its gravity.
And now scientists say they have discovered some new risks with long-term space flight. A study published recently in JAMA Network Open, a medical journal, examined 11 healthy astronauts who had been on the International Space Station for six months. Eight of them had unusual characteristics observed in their blood. For instance, six of the astronauts had reverse （反向的）blood flow from their heads.
The lead author of the study says he doesn't know if that's actually harmful. The blood is still leaving the head from other pathways, so flowing backwards through a jugular vein（颈静脉） may not be dangerous. But he says it does show a change in how blood moves through the body while in space.
Another issue the study found was blood clots （凝块）. One astronaut had one. Another showed signs of a partial blood clot. That is potentially harmful as the clots can block the flow of blood to the lungs. The astronaut who had one was treated for the rest of the spaceflight and made it home safely.
What does all this mean? Well, one researcher says these issues have probably been oc- curring since humans first went into space and that they would likely resolve themselves when astronauts came back down to Earth. Knowing about them now gives doctors something else to monitor when people leave our atmosphere.
1. What causes the physical problems for astronauts?| A．Sleeping for a long time. | B．The zero gravity environment. |
| C．Staying in the spaceship. | D．The shift in their bodies. |
| A．Four. | B．Three. | C．Two. | D．One. |
| A．It is a common problem. | B．It is a new kind of disease. |
| C．It is a threat to people's health. | D．It was first found by astronauts. |
| A．Doctors have a new task for astronauts |
| B．Zero gravity stops astronauts flying in space |
| C．It's dangerous for astronauts to fly into space |
| D．New risks are found in long-term space flight |
