1 . For millions of years, Arctic sea ice has expanded and shrunk in a rhythmic dance with the summer sun. Humans evolved in this icy world, and civilization relied on it for climatic, ecological and political stability. But now the world comes ever closer to a future without ice. The National Snow and Ice Data Center reported that 2019’s minimum arctic sea ice extent was the second lowest on record. Arctic summers could become mostly ice-free in 30 years, and possibly sooner if current trends continue. As the northern sea ice declines, the world must unite to preserve what remains of the Arctic.

Although most people have never seen the sea ice, its effects are never far away. By reflecting sunlight, Arctic ice acts as Earth’s air conditioner. Once dark water replaces brilliant ice, Earth could warm substantially, equivalent to the warming caused by the additional release of a trillion tons of carbon dioxide (CO₂) into the atmosphere and declining sea ice threatens wildlife, from the polar bear to algae that grow beneath the sea ice, supporting the large amount of marine life.

To avoid the consequences the scientific community should advocate not just for lowering greenhouse gas emissions, but also for protecting the Arctic from exploitation. The Antarctic shows the way. In the 1950s, countries raced to claim the Antarctic continent for resources and military installations. Enter the scientists. The 1957-1958 International Geophysical Year brought together scientists from competing countries to study Antarctica, and countries temporarily suspended their territorial disputes (争议). In 1959, 12 countries signed the Antarctic Treaty to preserve the continent for peaceful scientific discovery rather than territorial and military gain.

Sixty years later, we must now save the Arctic. A new Marine Arctic Peace Sanctuary (MAPS) Treaty would protect the Arctic Ocean as a scientific preserve for peaceful purposes only. Similar to Antarctica, MAPS would prohibit resource exploitation, commercial fishing and shipping, and military exercises. So far, only 2 non-Arctic countries have signed MAPS; 97 more need to sign on to enact it into law. Scientists can help—just as they did for the Antarctic—by giving statements of support, asking scientific organizations to endorse (支持) the treaty, communicating the importance of protecting the arctic to the public and policy-makers, and above all, by convincing national leaders to sign the treaty. In particular, Arctic nations must agree that recognizing the arctic as an international preserve is better than fighting over it. In 2018, these countries successfully negotiated a 16-year moratorium on commercial fishing in the Arctic high seas, demonstrating that such agreements are possible.

Humans have only ever lived in a world topped by ice. Can we now work together to protect Arctic ecosystems, keep the northern peace, and allow the sea ice to return?

3 . COVID-19 lockdowns had strange effects on air pollution across the globe

Ever since the covid-19 spread, many changes have come with the _____________ unstoppable virus. China has shown the first sign. Rightly after a strict nationwide lockdown was _____________ in late January, most people were restricted from leaving their homes at all for as long as 3 weeks. As a result, the authority ___________ a sharp decline in the direct emissions of air pollution on a scale never observed before. “Changes in emissions would be significant and ___________ studying for it may bring us new solutions to greenhouse effect,” says Jiset Deew, a chemist at the Harvard University, “The pandemic has caused lots of tragedies, but the lesson we can learn is important.”

Researchers found it a strange but ___________ chance to capture how human economic activity—particularly car traffic—dropped rapidly and thus to seek for the answer to the influence of ___________ traffic on air quality. “Running atmospheric chemistry experiments is often a ___________ task based on the lack of experimental conditions, so we have to _________ really complex reaction chambers and computer models,” says Tg, who now works on the project _____________ organic aerosols at MIT. “But in this unprecedented year, we finally get the chance to __________ our ideas and we hope the new findings will further our understanding of the mechanisms that rule atmospheric chemistry but also offer guidance for policy makers who seek to improve air quality and ____________ climate change.”

During the lockdown, passenger traffic plumbed, and traffic-related emissions—particularly CO₂ and NO₂—__________ accordingly. Vehicles powered by gas directly release huge amounts of CO₂ and NO₂. CO₂, a greenhouse gas, plays a major role in global warming. Besides, NO₂ plays a __________ part in atmospheric reactions that produce ozone which helps __________ UV light (紫外线). Now, experts are still working to __________ how the two gases changed during pandemic.

6 . How do you teach a monkey new tricks? Labs have proved difficult places to train monkeys to respond to different sounds, but in the forests of Senegal’s Niokolo-Koba National Park, researchers were astonished how quickly one species of monkey adapted its behavior to a new sound.

Julia Fischer at the German Primate Center in Gottingen and her team flew drones over a community of green monkeys in the area, to see what they made of a new flying object in their environment. They responded instantly, making alarm calls to warn one another of the potential new threat.

The vocalizations were distant from the ones they made in response to models of leopards and snakes, but almost identical to calls made by a related species of monkey about eagles. The results suggest a hardwired response to the perception of an aerial threat and the use of that specific call.

They monkeys adapted so quickly to the mechanical noise that they began scanning the skies and making the calls even when the sound of the drone was played from the ground. The monkeys were never seen issuing alarm calls in response to birds of prey in the area, suggesting that the birds they usually see aren’t considered a threat. The drones, however, seemed to be perceived as dangerous. “It’s certainly disconnecting, unpredictable, something they’ve not seen before, so it makes sense to alert everybody,” say Fischer. She says she was “blown away” by how rapidly the monkeys appeared to learn. “The listeners are smart. It’s almost impossible to get a monkey in a lab to do an audio task. It isn’t clear why such learning is harder in a lab environment,” she says.

The study involved a year’s worth of fieldwork by a team of eight, who flew the drone about 60 meters above the monkeys. The research wasn’t without incident. Fisher had to duck inside a shelter made of palm leaves at one point, after a baboon ran to attack the leopard model she was holding.

Vervet monkeys in East Africa are related to green monkeys. They have been closely studied for the different calls they make in response to a variety of predators, including pythons, leopards, baboons and martial eagles.

The expectation for the green monkey study was that they would stay silent. come up with a new alarm call or produce one similar to the velvet monkeys’ eagle call. Fischer’s bet was on the eagle call option, and she was proved right. The vocalization appears to be highly conserved by evolution. “It teaches us about how different their vocal communication system is from ours,” says Fischer. “There is a very limited level of flexibility.”

What Comes After Space?

Looking at a clear night sky you witness the vastness of space, which holds everything humans know to exist. To find out what     1     beyond a good place to start is to determine where the universe ends. However, the problem is that scientist are uncertain about where space ends or whether it ends at all.

The     2     universe

The furthest humans can see out into space,using all the technology currently available to us,is 46 billion light years (alight year is the distance that light can travel in one year,and is equivalent to about 9. 5 million million kilometres). The     3     of space that humans can see is called the visible universe. Beyond this, it remains a mystery whether it’s an expanse of more galaxies and stars or possibly the edge of the universe. Some think that the universe is     4    , meaning space goes on forever in every direction. In this case,there is nothing after space,because space is everything.

Moving further away

Experts have captured images of the entire Earth from space,and some astronauts have personally witnessed its beauty from orbit. Perhaps     5     the limits of the universe would also be possible too, if only humans knew where to go to look for it.

Another challenge is the universe’s rapid     6    . As galaxies move further away their light   takes longer to reach us. Eventually, some galaxies may be so distant that their light never     7    . This might imply that any edge— and whatever is on the other side — is increasingly     8     itself from us. Regardless of these uncertainties, scientists still spend a lot of time thinking about what comes after space.

Many universes?

It’s possible that there isn’t just one universe, and that our universe is just one small part of a “multiverse”. Perhaps our universe is     9     within its own distinct region of space, separated from others by vast expanses of nothingness. Or maybe     10     universes exist pressed tightly against each other. Getting an idea of the universe’s true shape may help astronomers find out whether it has an edge. What comes after that could be an even great mystery.

9 . The misery of my bike commute in Calgary, Alberta, is the river valley hill. It’s not particularly steep, but at about a mile long, I rarely climbed up without arriving with sweat. Studies have shown the prospect of arriving at work sweaty is one of the biggest _________ to getting would-be bike commuters out of their cars. That’s especially true in a city like Los Angeles, where _________ may face long routes , hills or hot streets with a lack of shade.

“Pedelec”, or pedal electric-assisted bikes like the one I rode, can end that worry. They look and act like traditional bicycles, but their motors make pedaling much easier when required. Sometimes called the most energy-efficient motorized mode of transportation ever built, they’re also incredibly green. The biggest barrier may be the outdated attitude that sees bikes only as a recreational athletic opportunity rather than a practical _________ option.

At a time when cities across North America are struggling to combat crippling traffic and reduce climate emissions, e-bikes have the _________ to ease the both problems. And yet ridership has yet to truly _______.About 152,000 e-bikes were sold last year in the U.S., a figure that would be more than 5 million if Americans used them at the same rate as western Europeans.   

Many of the barriers to e-bike _________in North America are legislative. Patchwork rules treat e-bikes more like mopeds than traditional pedal bikes in some jurisdictions,meaning they are _______from bike lanes and from boarding public transportation.

Few places on the continent, _________, are better poised to break through barriers than California. Legislation was approved last year to encourage e-bike use, by legally differentiating the cycles from mopeds. In an attempt to head off worries about turbocharged machines flying down sidewalks and bike lanes at unsafe speeds, the law classifies bikes into different tiers to _______ lower-speed e-bikes, which top out at 20 mph, from faster-moving “speed pedelecs”, which are restricted from protected bike paths.

Amid these legislative ________, e-bikes have become more accessible to consumer. Finding them in bike shops isn’t as __________ as it once was, and their cost has fallen as the price of lithium-ion batteries has dropped. Today, a decent e-bike, while still __________, is comparable in price to a high-end mountain bike. After years of ____________over mixing pedal and motor power, cycling advocacy organizations also are finally throwing their support behind e-bikes. Dave Snyder, the executive director of the California Bicycle Coalition, __________ the state’s new legislation based partly on the __________that e-bikes help out those who“just can’t ride as far or as fast as they need to”.