2 . A day in the clouds

The air is thin and we have to rest several times on the short hike(徒步旅行)from camp. To our left, snow-covered mountains disappear into clouds that seem almost close enough to touch. On the plain(平原) in front of us, we can just make out a herd of graceful animals. This is why we stay here.

Tibetan antelopes live mainly on the plains of Tibet. Watching them move slowly across the green grass, I'm struck by their beauty. I'm also reminded of the danger they are in. They are being hunted, illegally, for their valuable fur.

My guide is Zhaxi, a villager from Changtang. He works at the Changtang Nationa Nature Reserve(保护区) . The reserve is a safe place for the animals and plants of northwestern Tibet. To Zhaxi, protecting(保护)the wildlife is a way of life. "We're not trying to save the animals." he says. "Actually, we're trying to save ourselves."

In the 1980s and 1990s the population of Tibetan antelopes dropped by more than 50 Percent. Hunters were shooting antelopes to make money. Their Living places were becoming smaller as new roads and railways were built.

In order to save Tibetan antelopes, the Chinese government placed them under national protection. Zhaxi and Volunteers watched over the antelopes day and night to keep them safe from attacks. Bridges and gates were added to let the antelopes move easily and keep them safe from cars and trains.

The measures were effective. The antelope population has recovered and in June 2015, the Tibetan antelope was removed from the endangered species list(濒危物种名单). The government, however, does not intend to stop the protection programmes, since the threats(威胁) to the Tibetan antelope have not yet disappeared. Only when we learn to exist in harmony with nature can we stop being a threat to wildlife and to our planet.

2.只允许修改10处，多者（从第11处起）不计分。

Nowadays, the destruction of forests is one of most serious environment problems. From that I understand, people are destroying thousands of square kilometers of trees every day. This is killing hundreds of wild animals live in the forests. But something must be done. Unfortunately, we don’t do everything to protect the forests.

People who cut down trees should go to prison. That’s what happens in some country to people who sell plastic bags. That’s what should happened to people who destroy the forests. I can’t help but to think that we must protect wildlife for future generations. Hopeful, our children will be even much responsible that we are today.

4 . The world itself us becoming much smaller by using modern traffic and modern communication means (通讯设备). _________ today is much easier than it was hundreds of years ago, but it has brought new _________. One of the biggest is pollution. To pollute means to make things dirty. Pollution comes in many ways. We see it, _________ it, drink it and even hear it.

Man has been polluting the earth. The _________ people, the more pollution. Many years ago, the pollution was not so serious _________ there were not so many people. When the land was used up or the river was dirty in one place, man _________ to another place. But this is no longer true. Man is now slowly polluting the whole world.

Air pollution is now the most serious. It’s _________ for all living things in the world, but it is not the only one kind of pollution. Water pollution _________ our fish and pollutes our drinking water. Noise pollution makes us become _________ more easily.

Many countries are making rules to fight pollution. They __________ people from burning coal (煤) in houses and factories in the city, and from putting dirty __________ into the air.

Pollution by SO2 is now the most __________ kind of air pollution. It is caused by heavy traffic. It is true that if there are fewer people __________, there will be less air pollution.

The earth is our home. We must take care of it. That means __________ the land, water and air clean. And we must take care of the __________ in population at the same time.

7 . Twelve years ago, a young traveler named Rhett Butler from San Francisco, California, visited the Sabah rainforest on Malaysian Borneo. In one area of the rainforest, he watched a bird flying through the trees. The beautiful sight left quite an impression on him. But weeks later, back home, Rhett Butler got the news that trees had been cut down in the area he visited.

That experience led Rhett Butler begin writing a book about rainforests and threats to their existence. But he did not publish the book. Instead, in 1999, he used his research for the book to create a website. The site is Mongabay. Com. His purpose was to inform the public about tropical rainforests. But the subject quickly developed. As a former businessman, he became a respected writer of science and environmental stories.

The popularity of Mongabay. Com attracted advertisers. Small ads on the site pay for its operations. Mongabay.Com has grown and led to other sites. For example, there is a site for children which is called kids. Mongabay.Com. Another one, WildMadangascar.Org, is all about the island nation that Rhett Butler calls his favorite place.

To keep his website going, he travels around the world on several major trips each year. His working tools are a laptop computer, cameras and sometimes diving equipment. He often calls on experts for information. For example, he interviewed Alison Jolly, a top experts on lemurs(狐猴). He interviewed Rodney Jackson, a biologist who established the Snow Leopard Conservancy.

Stories like these have made Mongabay a favorite place on the Internet for researchers, students and teachers. In April, Time.Com named it one of the fifteen top climate and environment websites in the world.

8 . Illegally traded endangered species that escape, forming secondary populations, offer hope to their long-term survival, a study suggests. "This first came to my attention when I read a news story about the seizure of an illegal shipment of 23 yellow crested cockatoos (小葵花凤头鹦鹉),” said Luke Gibson, a college teacher. He learned that the species was critically endangered, which surprised him.

This encouraged Dr. Gibson and his colleague to investigate (调查) how a critically endangered species had become self-sustaining outside of its natural range. They discovered 49 cases of a globally threatened species becoming established as a separate population, which they hadn’t thought of, including the yellow-crested cockatoo in their city.

“This is a species which is primarily threatened by wildlife trade,” he told BBC News. “Poachers (偷猎者) go out into the forest in its native range in eastern Indonesia and capture the bird and then ship them off, usually up to our city where there is a strong demand for pet birds. This is what has fueled the decline of this species in its native range. But it’s really interesting because that same cause also had another effect: some of the people who were keeping this species here accidentally or intentionally released them.” As a result of enough of the birds set free, it allowed a new self-sustaining population to be established in this city.

The government in of Dr. Gibson’s city has made it illegal to capture the species, even though it is a non-native species. Because the city is affluent and relatively well educated, the cases of people breaking the law are extremely rare, explained Dr Gibson, unlike in its native range in Indonesia, where capturing birds form a major source of income.

However, there can be downsides (缺点) to the newly established population of endangered species, such as a limited genetic pool, and suffering from novel diseases. It did also present a possible “very interesting” opportunity for conservationists, Dr. Gibson suggested. This would involve “harvesting” some of the newly established secondary population, which may provide a way to help slow global biodiversity loss.

10 . In 2016, a team of Japanese scientists found bacteria capable of breaking down and “eating” one of the world’s most popular plastics-polyethylene terephthalate(PET). It was valued as a potential breakthrough at the time. But a new discovery came as a team of British scientists examined an enzyme(酶) produced by the Japanese bacteria to find out more about its structure. While operating the structure to better understand how it worked, they accidentally created the changed enzyme that’s even more efficient at breaking down plastic bottles.

The researchers are now working to further improve the enzyme so it can be used on an industrial scale. It’s possible that within the next few years there could be an industrially possible process for turning PET into other substances so it can be recycled.

The ability to scale up the process will be important. Plastic pollution is fast becoming one of the biggest environmental issues of our time. More than 1 million plastic bottles are bought around the world every minute. Most of these bottles are made from PET，which can take up to1000 years to biodegrade(生物降解), and many are left in the oceans. Over half of global PET waste is not collected for recycling and only 7 percent of bottles are recycled into new bottles.

Some scientists say the breakthrough, though promising, is nowhere near enough to solve our pollution crisis. These enzymes are not abundantly present in nature. So you would need to produce the enzyme first, then add it to the PET plastic to degrade it.”This is likely to be a slow process. If you have gone through the trouble of collecting the PET waste, then there are clearly far better ways to recycle it or burn it for energy,” said Wim, head of the Industrial Biotechnology Center. He suggested the use of commercially available biodegradable bioplastics would still be a better bet.