1 . Directions: After reading the passage below, fill in the blanks to make the passage coherent and grammatically correct. For the blanks with a given word, fill in each blank with the proper form of the given word; for the other blanks, use one word that best fits each blank.

The Mystery is No Mystery

The area of ocean between Florida, Puerto Rico, and Bermuda, known as the Bermuda Triangle, is the source of much mystery. Over the centuries, reports of ships and planes disappearing     1     a trace have seized the public attention, leading the zone     2     (nickname) “The Devil’s Triangle.” Suggested causes for these mysterious disappearances range front supernatural powers to underwater alien bases. However, there is a more basic question to ask: Do more craft really disappear in the Bermuda Triangle than in any similarly trafficked area? The answer,     3     it turns out, is no.

The Bermuda Triangle covers a vast 700,000 square-kilometer swathe of ocean. Close to the equator(赤道)and near the United States, it is a particularly busy patch of sea with heavy traffic. According to Lloyd’s of London and the U. S. Coast Guard,     4     you were to compare the number of disappearances to the large quantity of ships and planes that have passed through the Bermuda Triangle, you would find that there     5     (be) nothing out of the ordinary about the area.

These days, new theories are being put forward, with a bit of scientific truth to them. Some have attributed Bermuda Triangle disappearances to explosive releases of methane (甲烷) gas,     6     (trap) as methane hydrate inside water molecules beneath the cold seabed of the deep ocean. Such blowouts could potentially release a giant amount of gas that could cause the sea to bubble like it was boiling, which could possibly sink ships because the resulting bubbles would be much     7     (thick) than the water on which large ships normally float. The gas could also rise into the sky,     8     (produce) a mixture of five to 15 percent methane which could explode on contact with the engine exhaust of a hot airplane.

The only problem with this theory is that scientists won’t be able to tell with much certainty if this is a factor       9     the ocean floor is mapped in greater detail. It remains to be seen     10     they will succeed in their attempt to clear up the Bermuda Triangle “mystery” this time around.

Throughout the world, only 15% of the material that are used to make clothing is properly recycled, according to the Alle SacUrthur Club, an organization in Liverpool, UK, that boosts the circular economy. Most clothing waste—an     1    (estimate) 82 million tonnes from the fashion industry alone-produced every year ends up buried or burnt.

    2    (handle) all that waste, methods to recover and reuse the material are intended as an active response to the future risks by researchers and start-up companies. Much of their focus is on chemical recycling,     3     the material is broken down into its building blocks and applied to create new materials, including fibres that     4     (weave) into new clothes. The challenges lie in     5     (develop) the processes for such treatment. They have to be practical, but they also have to be at least as cost-effective as simply making new fibres.

    6     the natural cellulose fibres from cotton, some other materials include human-made cellulosic fibres. They are derived from wood-pulp cellulose and may be used to produce materials such as viscose (rayon) and a similar material called lyocell.

A change in the manufacturing process is being applied to the textile-waste problem by Essen, a start-up in Seattle, Washington.     7     the company has fundamentally devoted to the process is that it uses discarded textiles, instead of wood, as the source of its cellulose. It has also adjusted the process to produce a fibre that the firm’s co-founder and president Christo Stan says is superior to     8     other cellulosics and cotton, and that can be recycled more times.

Although there are abundant technical challenges, the main barrier     9     widespread textile recycling could be economic, says materials engineer Lijiang Jiang at the Massachusetts Institute of Technology in Atlanta. “Most of the materials are not that invaluable,” Jiang says. So cheap it is to produce polyester, cotton and other fabrics     10     there’s little profit margin unless the recycling processes themselves are very inexpensive.

Sky Kurtz farms in the desert. The co-fbunder and CEO of Pure Harvest Smart Farms—    1    (locate) outside Abu Dhabi, where temperatures regularly top 113°F—and his team use the challenging environs to trial new crops and technologies that have the potential to change farming in climate-challenged areas. Pure Harvest also provides produce to supermarkets and restaurants in Dubai and across the region     2    (use) less water, which is important in one of the most arid regions of the world.

Kurtz founded Pure Harvest Smart Fanns in 2017 with his co-founders Mahmoud Adi and Robert Kupstas. Passionate about food insecurity, they spent the first year studying high-tech food-production systems around the world,     3     searching for the optimal site for their first farm.

Kurtz’s farms in the UAE started out with “    4     but a PowerPoint, a pile of dirt, and the promise of what we would do,” says Kurtz. But Pure Harvest quickly proved it was built on more than a promise. The founders’ research and technological innovation led to the development of a proprietary (专利的)Controlled-Environment Agriculture (CEA) system—a combination of high-tech greenhouses and vertical farms that     5     (provide) a stable year-round climate.   The first crop of tomatoes was planted in August 2018 and harvested in October. The company’s original farm is now its R&D facility, and Pure Harvest has expanded its facilities in the UAE to 16 hectares of growing area. It also operates a 6-hectare farm in Saudi Arabia, and is developing a 6-hectare farm in Kuwait.

It now produces 14 types of leafy greens; two varieties of strawberries, with seven more     6    (develop); and almost 30 varieties of tomatoes, the product that started it all. With limited availability of local, seasonal produce, the UAE has typically imported much of its food, often air-freighted,     7    comes at a high cost, both economically and environmentally. And while they are more expensive compared with locally grown seasonal produce, the company says its fruit and vegetables are typically up to 60% cheaper than air-freighted imports of comparable quality. “I think we’ve fundamentally changed a belief system that said local is     8    (bad).” says Kurtz.

Their vision fits in with a larger objective for Dubai to become more self-sufficient. The focus is not just on growing for premium markets but also developing affordable solutions    9    (help) democratize access to fresh food.

Kurtz hopes the company’s data-driven technology can become a model for other regions that are experiencing climate stress. “We believe that we can develop a local-for-local solution     10     it’s needed most, and we’ve battle-tested that capability in one of the harshest environments in the world." he says.

Forests give us shade, quiet and one of the harder challenges in the fight against climate change. Even as we humans count on forests to soak up a good share of the carbon dioxide we produce, we    1     (threaten) their ability to do so. The climate change we are hastening could one day leave us with forests that emit more carbon than    2    absorb.

Thankfully, there is a way out of this trap—but it involves striking a subtle balance. Helping forests flourish as valuable “carbon sinks” long into the future    3       require reducing their capacity to absorb carbon now. California is leading the way, as it does on so many climate efforts, in figuring out the details.

The state's proposed Forest Carbon Plan aims to double efforts    4    (thin) out young trees and clear brush in parts of the forest. This temporarily lowers carbon-carrying capacity. But the remaining trees draw a greater share of the available moisture, so they grow and thrive,     5    (restore) the forest's capacity to pull carbon from the air. Healthy trees are also better able to fend off (抵挡) insects. The landscape is considered less easily burnable. Even in the event of a fire, fewer trees    6     (consume).

The need    7    such planning is increasingly urgent. Already, since 20l0, drought and insects have killed over 100 million trees in California, most of them in 2016 alone，and wildfires have burned hundreds of thousands of acres.

California plans to treat 35,000 acres of forest a year by 2020, and 60,000 by 2030—financed from the proceeds of the state's emissions-permit auctions. That's only    8     small share of the total acreage that could benefit, about half a million acres in all, so it will be vital to prioritize areas at greatest risk of fire or drought.

State governments are well accustomed to managing forests,     9     traditionally they've focused on wildlife, watersheds and opportunities for recreation. Only recently have they come to see the vital part forests will have to play in storing carbon. Califomia's plan,     10     is expected to be finalized by the governor next year, should serve as a model.

Scientists have discovered that dogs produce more facial movements when a human is paying attention to them than when they are being ignored or presented with a tasty small piece of food.

The research argues     1     the belief that animal facial expressions are largely unconscious movements, that reflect internal sentiments, rather than a way to communicate.

Their expressions are responsive to humans — not just to other dogs. That shows us how domestication     2    (shape) them.

“Facial expression is often seen as something that is very emotionally driven and is very fixed, and so it isn’t something that animals can change     3    (depend) on their circumstances,” said Bridget Waller, professor of evolutionary psychology at the University of Portsmouth, and an author of the study.

Researchers     4    (involve) in the study published in Scientific Reports, used a video camera to record the facial movements of 24 dogs over a series of experiments     5     a human either faced the animal, or faced away, and presented the dog with a tidbit (小片食物), or did not. The recordings were then examined by the team frame by frame     6    (determine) changes in the facial muscles of the canines.

The results reveal that the dogs produced far more facial expressions when the human was facing the dog, than when they turned away — in particular, the animals were     7    (likely) to show their tongues and raise their inner eyebrows.

But the presence of food had no impact on the animals’ expressions. That suggested canine facial expressions were not just down to excitement, and cast doubt over     8     dogs use their facial expressions to twist their owners around their paws, said Waller.

“We wanted to see if dogs would produce the most facial expressions when they saw the face and the food, because that might then tell us they are trying to intentionally manipulate the human in order to get the food — and we didn’t see that,” said Waller.

The study suggested doggy expressions were not simply the result of internal emotions, but     9     be a mechanism of communication. The team noted their work didn’t show whether dogs simply learn to pull faces when a human pays attention to them, or whether it reflects a deeper connection. But, they said, it was notable that the animals tended to make their eyes appear bigger —     10     trait humans are known to find cute.

The First Space Cat

In a few weeks, space scientists will celebrate a remarkable event — the 60th anniversary of the launch of the first cat into space, an astronautical success that has never been repeated.

In the early 60s, dogs and monkeys were the animals usually used by scientists to find out exactly     1    dangerous the conditions were in outer space. And they were also used to assess if humans     2     survive trips beyond the edge of Earth’s atmosphere.

A total of 14 street cats     3     (gather) at France’s space agency for selection as cat astronauts, but the cats were not given names on purpose in order to prevent scientists from becoming too fond of them. The cat selected to travel to space was simply known     4    C341. C341 flew on a French rocket in October 1963, taking it to a place     5    no cat had gone before.

Then,     6    the news of its flight was announced on 18 October 1963, the French press decided this cat had to have its name. They picked “Felix” after a cartoon cat character, only     7     (discover) that C341 was female, so her name was then adjusted to “Felicette” as a result. In putting Felicette in one of its rockets, France added a new species to the list of animals that scientists     8     (send) into space before. Previously, two garden spiders, Anita and Arebella, had been taken to the Skylab     9    (orbit) around the moon.

“In the 60s,     10    (concern) about the possible danger for a human to be in outer space, scientists and engineers primarily undertook animal space flights to see if they suffered or their lives were threatened by the weightlessness or increased radiation or other effects they might experience up there,” said astronomer Jake Foster at the Royal Observatory Greenwich. “The fact that they did not fail paved the way for humans to begin journeys into space.”

Lovely Team Members

I fell in love with rhinos when I worked in a zoo in the 80s, and spent much of the next 20 years as the keeper of the largest captive (圈养的) group of rare black rhinos.

Being aggressive and stupid is     1     impresses urban residents about rhinos, but I discovered a group of sensitive, affectionate animals.     2     (weigh) over a ton, black rhinos are unexpectedly alert and have an unpredictable nature. However,     3     care and reassurance (安慰), they can be very trusting.

In the past few years, the number of rhinos has dropped dramatically, during     4     time I have helped look after rhinos being moved to reserves. Last year, I helped on a project to fly five black rhinos to the Serengeti National Park, where they had to be kept captive for a few weeks before     5     (release) into the wild. They lived in “bomas” wooden enclosures with “bedrooms”.

A couple of weeks before their planned release, the sky was filled with smoke and the flames were blowing over it.     6     (make) sure everything was fine, we rushed toward the bomas. I was terrified that the rhinos     7     (catch) fire, so my initial response was to release them. But I couldn’t, because they     8     (not fit) with transmitters (发射器). If I let them out, we would have great difficulty tracking them down. So I dashed back to the bomas and called the rhinos to their “bedrooms”. To my surprise, they moved without hesitation and were     9     (panicky) than I had thought. After half an hour, the wind changed direction and the fire began to die down.

That we and the rhinos had escaped unscathed (未受伤的) was a miracle. The relationship we had built with those lovely animals proved crucial.     10     it, all our work would have been for nothing. The teamwork of everybody there played a large part too and the rhinos were very much part of that team.

The Real Cost of Travel

Mass tourism is a relatively recent phenomenon. The tourism industry     1     (take) off in the middle of the last century and it’s been growing ever since. In the last ten years especially, more and more people have been traveling to places     2     we had previously only read about or seen on television. But what kind of impact does tourism have on the planet?

A voyage to the end of the earth?

A large cruise ship (邮轮) can carry as many as 6,000 passengers and there are upwards of 50 such ships currently     3    (sail) the seas. Cruise ships dump about 90,000 tons of waste into the oceans every year. Any harmful effects of this are made even worse by the fact     4     cruises tend to visit the same places over and over again, thus concentrating the waste in specific places.

Trash on top of the world

From remote ocean habitats to the world’s highest mountain, our trash is everywhere. Though far fewer people go climbing the Himalayas than on a cruise, their impact     5    (still feel). Tourism is vital to the economy of Nepal,     6     it is to many non-industrial countries. But for decades, climbers have been abandoning their unwanted equipment on Everest. For the last few years, clean-up teams of local and international climbers have been organizing hiking trips just     7    (pick) up the waste. One group has brought over eight tons of waste down from the mountain!

When more is not better

Tourism of a different kind is causing problems in Europe. Construction on the Mediterranean coast has been     8     control for years. Beach resorts form an almost unbroken line from Gibraltar to Greece, and natural habitats have disappeared under miles of concrete. And so we pollute the sea, the land, and the air. Low-cost air travel is booming, in spite of (or perhaps     9     (help) by) economic problems. For many Europeans, low-cost flights allow them to take several short vacations a year. Yet curiously, short flights actually have a much bigger effect on climate change than long flights. So, are there    10     (damaging) ways of seeing the world? Traveling by train, for example, is a much greener way of getting around.