2 . Otters, are cute, this no one can deny. They have big eyes, short and flat noses and claws (爪子) like tiny hands. They look even cuter when they wear hats and throw food balls into their mouths as if they were bar snacks, like Takechiyo, a pet otter in Japan. Documenting Takechiyo’s funny behavior has earned his owner nearly 230,000 followers on Instagram, a photo-sharing app.

Takechiyo’s fame reflects a craze across east and South-East Asia for keeping the cute creatures as pets. Enthusiasts in Japan visit cafés where they pay to hug them; Indonesian owners parade their pets around on leads or go swimming with them, then share their pictures online. But these enjoyable photos mask a trade that is doing a lot of damage. Even before they became fashionable companions for humans, Asia’s wild otters faced plenty of threats. Their habitats are disappearing. They have long been hunted for their coats, or killed by farmers who wish to prevent them consuming fishes. The pet trade, which began picking up in the early 2000s but appeared to speed up a few years ago, has made things worse. The numbers of wild Asian small-clawed otters and smooth-coated otters, two species that are in highest demand, have declined by at least 30% in the three decades to 2019.

The international agreement that governs trade in wildlife, known as CITES, now prohibits cross-border trade in these species. But laws banning ownership are often poorly implemented, as in Thailand, or full of holes, as in Indonesia. And the otter-keeping craze has been dramatically improved by the internet, says Vincent Nijman of Oxford Brookes University. In 2017 TRAFFIC, a British charity that monitors the wildlife trade, spent nearly five months looking at Facebook and other social-media sites in five South-East Asian countries. During that time, it found around 1,000 otters advertised for sale online.

In any case, otters do not even make particularly good pets. Every year the Jakarta Animal Aid Network, a charity in Indonesia’s capital, receives some ten otters from people who have struggled to look after them. Faizul Duha, the founder of an Indonesian otter-owners’ group, admits that his two animals emit a “very specific” (read: fishy) smell. They bite humans and chew on furniture. Their scream can be heard blocks away. And their cages need cleaning every two-to-three hours. That is how often they empty their bowels (肠道).

4 . Bringing Mosquitoes Under Control

Every year, hundreds of thousands of people die of mosquito-borne diseases like malaria and dengue fever. Drug treatments are ________, and, despite decades of effort, vaccines have, for many of these diseases, proven to be difficult to develop.

It is better, then, to stop these infections happening in the first place by ________ doing away with the mosquitoes that carry the diseases. CRISPR-Cas9, a new and powerful genetic-engineering process, could help to do just that.

Craig Montell, of the University of California, and his colleagues have used CRISPR to ________ an existing control method called the sterile insect technique (SIT), which involves releasing lots of sterilized (绝育的) males into the wild. Females that mate with these males produce no young. ________ releases can reduce populations dramatically. SIT has been used in North America to eliminate screwworm flies, an agricultural pest.

SIT has been tried on mosquitoes, too, but with less ________. One reason seems to be the side-effects of the procedure. To sterilize them, males are exposed to poisonous chemicals. This works, but it damages them in other ways, too. The result can be sickly individuals that ________ to compete in the mating game with wild mosquitoes.

Montell and his colleagues hoped that CRISPR might offer a(n) ________. Their first step was to look for genes which affect fertility (可繁殖性) in mosquitoes. They began their hunt in fruit flies and ended up focusing on a gene that, when ________, made male fruit flies sterile. The gene was present in a similar form in their target mosquito species, Aedes aegypti, which passes on, among other illnesses, yellow fever, dengue and the Zika virus. Disabling the ________ gene in male Aedes likewise left them infertile. ________, the genetic changes involved did not appear to affect the engineered mosquitoes in any other way. On every measure of ________, they performed as well as wild mosquitoes.

________ the details are not fully understood, once female mosquitoes have mated a few times, they become unwilling to do so again. Mating with an infertile male is, therefore, not only fruitless in itself, but should also leave a female less interested in ________ males.

There is more work to be done before field trials, but having established the ________, Montell is excited to see where the work might lead. That the engineered males leave no young means that there are fewer worries surrounding any ________ consequences which might arise from the release of millions of genetically edited creatures into the environment. And that the target gene is found in both fruit flies and Aedes suggests it is likely to exist in other disease-carrying mosquitoes, too.

Animal Communication

Many pet owners long to talk with their animals. After all, if pets were able to talk, people could take care of them more easily and have closer emotional     1     to them, so a number of companies are working on devices and apps that could translate what animals say.

One such app is called MeowTalk. Using voice recognition software, this app recognizes different sounds a cat makes and offers English translations of them. For example, one type of sound might mean “feed me” while another could be translated “let me outside.” The app can use machine learning to assess its translations and improve at recognizing one particular cat’s voice. In other words, it can     2     in understanding your cat in particular. This is important because cats do not all have a(n)     3     language, but individual cats frequently use particular sounds to mean certain things.

In the future, MeowTalk could connect to a smart collar that would hear the cat meow and play the translation out loud. Perhaps if the cat is outside and needs to be let in, it could even send     4     to the owner’s phone.

For dogs, a Japanese company called Inupathy has developed a harness (保护带) with a heart rate monitor and an app. The heart rate monitor is used to assess a dog’s     5    . This is possible because, like humans, dogs’ heart rates go up when they are excited or     6    . The harness also has a light that turns red when the dog is excited, but when the dog is relaxed, the light is blue.

The most obvious use of this technology is to help pet owners     7     with and provide for their pets better. The more owners know about their pets, the easier it is to meet their needs.

There are other     8     of technology that help us understand animals. For example, some sheep farmers are using artificial intelligence to scan and determine if they are in pain, which helps them find out sick animals. As a result, they can     9     more quickly to treat the animal.

Anyone who interacts regularly with animals could benefit from understanding their animals better. Thus these     10     developments might transform the way we interact with the creatures around us.

7 . It took brave European explorers less than 300 years, between 1420 and 1713, to establish that all the seas of the world formed an enormous and continuous ocean. This discovery encouraged them to _____ into areas which hadn’t been charted until then. With the discovery of new lands, new trade routes were _____. In many parts of the world, colonies and settlements were established and many odd-looking products were brought back to _____, arousing great interest and _____ wealth.

It was probably the irresistible desire for wealth that _____ persuaded Europeans of the fifteenth century to _____ their legendary dangers and explore further out into the open seas. They were also _____ by the love for their countries. Many explorers wanted to serve their kings and countries as well as gain personal _____ from their exploring.

The most effective way of gaining wealth was through _____. Silk, gold, silver and ______ stones, and more importantly spices, such as gingers and peppers, were the most profitable trade goods in Europe. Spices were of the greatest ______ because they enabled the Europeans to make their winter diet of salted meat more delicious. These items were ______ mostly from the East by a difficult overland route. The Italian ______, who bought goods from the Arabs of Alexandria, controlled the trade along this route. Other countries of the Mediterranean ______ the wealth which this trade generated and they were ______ to discover new routes which would allow them to share in it.

8 . Because of the politics and history of Africa, wild animals there, which are interested in finding food and water not in politics, are in trouble. In the past, there were no borders between African countries, and the animals could travel freely according to the season or the weather. However, in the 19th and 20th centuries, the continent was divided up into colonies and then into nations. Fences were put up along the borders, so the animals could no longer move about freely.

Some countries decided to protect their animals by creating national parks. Kruger National Park, created in South Africa in 1926, was one of the first. By the end of the twentieth century, it had become an important tourist attraction and a home for many kinds of animals. Among these, there were about 9,000 elephants, too many for the space in the park. It was not possible to let any elephants leave the park, however. They would be killed by hunters, or they might damage property or hurt people. South African park officials began to look for other solutions to the elephant problem.

As early as 1990, the governments of South Africa and Mozambique had begun talking about forming a new park together. In 1997, Zimbabwe agreed to add some of its land to the park. A new park would combine the Kruger National Park with parks in Mozambique and Zimbabwe. There would be no national border fences within the park, so that elephants and other animals from the crowded Kruger Park could move to areas of Mozambique and Zimbabwe. This new “transfrontier” park would cover 13,150 square miles (35,000 square kilometers). The idea of a transfrontier park interested several international agencies, which gave money and technical assistance to Mozambique to help build its part of the park.

In April 2001, the new park was opened, with new borders and a new name: The Great Limpopo Transfrontier Park. A border gate was opened between Kruger National Park and Mozambique, and seven elephants were allowed through. They were the first of 1,000 elephants that would be transferred to the world’s greatest animal park.

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.