2 . If a scientist sees a unicorn (独角兽), she’ll probably want to see more than one before telling the world about her discovery. But sometimes one unicorn is enough.

In 2007 an astronomer named Duncan Lorimer reported finding a new kind of astronomical event. It was a brief stream of energy so powerful that it could reach Earth from a galaxy billions of light-years away. He called it a fast radio burst (FRB). This remarkable find, if real, could make huge contributions to the study about universe. He predicted there would be many more – but that year, he spotted just one.

It’s not unheard of for one event to kick off a whole new field of scientific inquiry. Still it’s rare. When Lorimer’s paper came out in the journal, it was not surprising that many were skeptical. “Sometimes, what seems like a remarkable scientific discovery turns out to be an error in the data,” some commented.

Later, a young graduate student was assigned the task of finding more FRBs. Using the same radio telescope Lorimer once used, she found more bursts that just looked like FRBs. But because of the ways they appeared in the telescope data, she was virtually certain that they were some other kind of radio interference and gave them another name: perytons. As years ticked by and no more FRBs were discovered, some astronomers began to conclude Lorimer had found nothing more than an unusual example of one of these perytons.

Good news: in 2011, there was a report of a second FRB. Four more were found in 2013. Bad news: all of them came from the same Lorimer’s radio telescope. But ultimately, in 2014, there was a report from another radio telescope. More discoveries started showing up from other telescopes on a somewhat regular basis. At last the conversation about FRBs shifted – from whether they were real to where they came from.

Years of research have passed by since then. Now, Victoria Kaspi, a physics professor and principal investigator on the FRB team, predicts that once the more advanced telescopes come online in 2024, the location and distance of most FRBs detected can be found out, which will provide “golden opportunities for astronomers to study the large-scale structure of the universe”.

Finally, this “unicorn” story came to a somehow surprising end. Several years ago, a team reanalyzed the same data from the radio telescope by which Lorimer found the first FRB. There was one more that they had previously missed. Since then, other teams have analyzed even older data and found FRBs in those datasets too.

“They were just sitting there, waiting to be discovered by better techniques,” Lorimer says.

3 . Gone are the days when big businesses were looked upon by environmentalists as enemies in the fight against global warming.

Just two weeks after U. S. President Donald Trump pulled his country out of the Paris Climate Agreement, more than 900 American firms put their _______to a “We Are Still In” open letter to the United Nations. Together, they promise to help reduce America’s carbon emissions by 26 percent by 2025, _______the Paris Climate Agreement.

_______, big businesses have been taking climate change seriously for years now. Alongside energy-efficiency measures, the strongest evidence of their _______has been the number of new wind and solar projects that they have been helping to build around the world. IT firms such as Amazon and Google have been using clean energy to power their servers (服务器). Some environmentalists now believe that big businesses could become strong _______behind the worldwide spread of renewable energy. “There used to be little action,” says Marty Spitzer of the World Wildlife Fund (WWF), “Now, I see fundamental _______being made.”

More recently, this enthusiasm for environmental protection has _______from corporate headquarters to branches and suppliers, and from developed countries to emerging markets. Take Walmart, the world’s largest retailer, for example. In March 2016, it said that it would require its own operations and those along its _______chain to reduce carbon-dioxide emissions by one billion tons by 2030. This is _______to taking 211 million passenger cars off America’s roads for a year. The announcement was ________by the WWF and other conservation organizations, which are helping Walmart’s suppliers work towards this goal. Apple, maker of the iPhone, has said that seven of its biggest global manufacturers have promised to power their Apple-related ________with renewable energy by the end of this year.

According to the WWF, in the United States alone, nearly two dozen of the biggest firms have committed themselves to becoming 100 percent renewable in the near future. Hervé Touati of the Rocky Mountain Institute, a clean-energy research firm, explains the ________behind this trend. Going green improves the companies’ public image and helps attract customers, staff and investors.

Anheuser-Busch InBev, the world’s biggest brewer (啤酒公司), has lots of young people among its many ________. Many of them take environmental issues seriously. Electricity, used ________in the brewing process, amounts to a tenth of its total costs. Last year, the company set out to increase the role of renewables in generating ________to 100 percent by 2025. “My generation often takes energy and clean air for granted,” said Tony Milikin, the firm’s chief sustainability officer. “The generation coming up now looks at it totally differently.”

4 . Strengthen Bonds With Your New Pet

Welcoming a new pet can be a magical moment for a lot of families. Unfortunately, many new pet owners struggle to bond with them. The following steps may help.

This should go without saying but spending time with your pets can greatly help you form a strong relationship. Pets love to be included in every activity of their humans, whatever the activities are.     1     Cats love playing with yarn (纱线) balls and fishing pole toys. Dogs are outgoing and usually love playing games with tennis balls such as fetch. So it’s also important to learn what type of play your pet enjoys.

Most people forget that training and teaching them tricks is a healthy outlet as well.    2     Whether you’re teaching them simple commands like ‘sit’ or something more complex like ‘turn around’ or ‘bow’, they’re sure to enjoy your company and will love you all the more for your attention, company and praises. Pets also love being rewarded with treats.     3     Moreover, when they begin to anticipate treats for good behaviour, they are more likely to be on their best behaviour, further making you and your pets grow closer.

One more thing to notice is that taking care of a pet can be a wonderful experience and also be quite frustrating. For new pet owners, it can be confusing, especially if you don’t understand what your pet needs or wants at any given time.     4     This might take a day or two, or might take months. But eventually, you will reap what you sow.

5 .

Lego: One Step Closer to Being Sustainable

The Lego Group is one step closer to reaching its goal of making all its products from sustainable materials by 2030.

The Danish toymaker revealed a prototype (雏形) brick made from     1     plastic. In a news release, Lego said the PET plastic from     2     bottles makes up the first brick to meet the company’s “strict quality and safety requirements.” One way the company     3     safety is by sourcing materials from suppliers that use processes approved by the US Food & Drug Administration and European Food Safety Authority.

“The biggest     4     on our sustainability journey is rethinking and innovating new materials that are as long-lasting, strong and high quality as our existing bricks—and fit with LEGO elements made over the past 60 years,” Lego Group Vice President of Environmental Responsibility Tim Brooks said. “With this prototype we’re able to    5     the progress we’re making to the public.”

It will be “some time” before bricks made from used materials can be     6    , Lego said. The company will continue to test and develop the PET formulation (配方) and decide whether to move to the     7     production phase, which is expected to take at least a year. One factor the company is testing is how the material can be     8    .

“Experimentation and failing is an important part of learning and     9    . Just as kids build, unbuild and rebuild with LEGO bricks at home, we’re doing the same in our lab,” Brooks said.

The move follows last year’s announcement that the company was making a $400 million investment over three years into sustainability     10    . It included phasing out the single-use plastic bags from its boxes and instead using recyclable paper for its packaging.

8 . On the mantelpiece is a sign saying “A home is not a home without a dog”. Next to it, in the couple’s living room, is a framed picture of a dog, which is itself nestled among ________ dog decorations. The kitchen, where Laura Jacques and Richard Remde’s four dogs ________ play and rest, is similarly decorated. Upstairs is the couple’s super king size bed, roomy enough to ________ two humans and four dogs.

Visitors to this house in Silsden, West Yorkshire are left in no doubt about the ________ of dogs in the couple’s lives. Their four dogs will soon become six, when they bring home two more cloned dogs.

Jacques works as a dog-walker. She has studied dog ________ and has spent a lot of time volunteering at the Dogs Trust. The couple have just moved into a new house, one they bought because it has a lot of land for the dogs to run around in. One corner has been ________ as a pet graveyard. Dylan, their eight-year-old dog who died earlier this year is to take the first ________.

When Jacques received the news from the vet that Dylan had died, she ________ in shock and grief. “I couldn’t comprehend that the worst possible thing had happened. I was just in total shock,” she says. “And then an idea occurred to me – I want to clone Dylan.”

The couple say they know how ________ pet cloning is and that some will criticize them for “playing God”. But they ________ that they are doing nothing wrong. “We have helped to make a scientific ________,” says Jacques. “Arguably dog breeders are doing something ________ but they are doing it for money while we aren’t. I can understand the ________ around human cloning – creating beings that don’t have a real mum or dad – but the same thing doesn’t apply to dogs. I know that some people will disagree with what we’ve done but I hope they won’t ________ us.”

They accept that some people will say they are mad and wonder why they are spending $100,000 on the ________. “We are not mad,” says Remde, “We are dog-mad though, and we both absolutely love all animals.”

9 . In recent weeks, a group of 15 wild elephants on a long, strange trip out of the jungles of far southwestern China have attracted millions of people across the country. Since the elephants left a wildlife reserve near China’s border with Laos and Myanmar last year, they have _________ steadily northward and have been wandering the suburbs of Kunming, a city of 8. 5 million residents.

Millions have _________ to watch the elephants’ 300-mile journey on television and on internet live streams, or tracked their movements on social media. While _________ with the creatures, some increasingly see the elephants and their journey as a lesson on the risks of nature and a rapidly urbanizing China crashing into one another, especially as development _________.

Videos of the _________ elephants, wandering down empty streets, breaking into a car dealership and in the case of one mother elephant using her trunk to lift her baby out of danger, have gone _________. Along the way, the elephants have broken into villagers’ homes, eaten their food, drank their water and destroyed their crops. All told, the group has now caused more than 400 separate incidents of damage, worth some $1. 1 million.

_________, authorities have formed a government task force. They mobilized hundreds of people, and distributed drones with infrared (红外线的) capabilities to _________ them as they wander through China’s Yunnan province. To keep the elephants away from more densely populated villages, authorities have blocked roads with trucks. Local authorities have been experimenting with snacks to _________ the elephants, laying out corn, bananas and pineapples. The __________ so far: The elephants like corn, while the pineapples have been largely ignored. The elephants have shown a continued interest in wooden buckets of alcohol.

Some specialists at the Chinese Academy of Sciences have assumed that a recent solar storm may have __________ the creatures’ inner compass (指南针) and triggered (引发) a(n) __________ to head north. Some scientists have theorized that the elephants are on the move because their __________ has shrunk while their population has grown.

In recent days, the __________ obsession among the elephants’ new fans has given way to __________ over the unintended consequences of China’s prosperity and economic development. “We’ve made a lot of money, but all these human activities have also caused a lot of trouble for the elephants,” says Mr. Liao, the truck driver, who says he has been inspired to pay more attention to wild animals and their habitats.