2 . How do you deal with plastic bags from the supermarket？Throw them away or recycle them? How about eating them?

The bags are no harmful to the environment.Humans and animals can safely eat them.Indian company EnviGreen has made a bag with natural materials.It looks and feels just like plastic，but can be broken down(分解) easily.

Ashwath Hedge who set up the EnviGreen company spent four years doing experiments(实验)with 12 natural materials.They include potato，corn，vegetable oil and banana.He made the materials into liquid(液体) and used the liquid to make the bag.

Although the EnviGreen bag is more expensive than a common plastic bag，it has many advantages.According to the Wall Street Journal，it takes 1，000 years for common plastic bags to break down.But an EnviGreen bag can naturally break down in less than 180 days.It also breaks down in less than a day in water，and in less than a minute in boiling water. Hedge was happy to show it in his interview；he put an EnviGreen bag in water and ate it with a smile.

There are more that 15，000 tons of plastic waste in India every day.But only 9，000 tons are processed.In China，3 billion plastic bags are used every day.Maybe the EnviGreen bag could be a solution(解决办法) to the world problem of plastic pollution.

4 . ''It can't be done. '' Boyan Slat heard this over and over when he first proposed a way to clean up millions of tons of plastic polluting our oceans.

Slat, who grew up in the city of Delft in the Netherlands, was on a diving trip in Greece three years ago when he was deeply impressed by plastic. ''There were more plastic bags than fish, '' he says. ''That moment I realized it was a huge issue and that environmental issues are really the biggest problems my generation will face. ''

That fall, Slat, then 17, decided to study plastic pollution as part of a high school project. Soon, Slat learned that no one had yet come up with practical way to clean up this massive garbage patches. Most proposed solutions involved ''fishing'' up the plastic using ships equipped with nets—which, as Slat discovered, would likely take more than 1,000 years, cost too much, let off too much sea life along with the trash.

Slat proposed an alternative that mostly avoided these problems: a solar-powered system using a floating plastic tube which will go around the garbage and trap it is 600 meters long. Wind, waves and ocean currents will push the trash toward the tube. A ship will pick up the trash and take it back to the shore. Best of all, Slat predicted his system could clean up the North Pacific Garbage Patch within five to 10 years.

The following, Slat entered the aerospace engineering program at the Delft University of Technology and officially announced his ocean cleanup concept at TEDxDelft. But nothing much moved forward.

Slat organized a team of volunteers and employees for The Ocean Cleanup, which now numbers about 100. In answer to opposition, Slat and his team raised $100,000 from a crowd funding campaign and began testing a 40-meter collecting barrier near the Azores Islands last March.

Over the next three to four years, Slat will push toward a fully operational large-scale project by testing a series of longer and longer barriers.

5 . Plans to bring wild tigers back to their original home , their historical range(历史分布范围） in the Ili­Balkhash region, have been announced by Kazakhstan( 哈萨克斯坦 )   and an agreement with World Wide Fund for Nature (WWF) to conduct a tiger reintroduction program has been signed . “It will not only bring wild tigers back to their original home, but also protect the unique ecosystem of the Ili­Balkhash region，” said Askar Myrzakhmetov, the Minister of Agriculture of the Republic of Kazakhstan.

If successful, Kazakhstan will be the first country in the world to bring wild tigers back to an entire region where they have died out for nearly half a century. Tiger reintroduction projects have only been achieved within national borders and in areas that are considered current tiger habitats . Kazakhstan's tiger reintroduction program is unique and it badly requires the restoration of a vast forest that is part of the wild tiger's historical range.

Since the beginning of the 20th century, wild tigers have lost over 90 per cent of their historical range. Wild tigers have completely disappeared from the region since the late 1940s, due to the loss of habitat. To prepare for the return of wild tigers, on 1st January 2018 Kazakhstan will set up a new nature reserve in the southwestern Ili­Balkhash, in order to restore the unique forest habitat. This will include the protection of existing wildlife, and reintroducing important prey ( 猎物 ), such as the endangered wild Bactrian deer（中亚红鹿).

Restoring tigers will also help protect Lake Balkhash and prevent it from repeating the fate of the Aral Sea, formerly the world's fourth largest lake and now 10 percent of its original size. “The hard work remains ahead of us. We have to spare no effort to make this region ready for tigers and involve all the relevant people to make this happen. That means dealing with illegal activities, having these people who govern parks be well­trained and equipped, increasing prey populations and involving local communities，” said Ekaterina Vorobyeva, Director of the WWF program.

6 . The amount of rubbish that piles on our shore lines is hugely worrying and a growing problem for the planet. It seems like no matter how remote you hike and how high you climb, there’s always a dropped plastic container there waiting for you.

Mariah Reading, an American artist, spends the majority of her time outdoors looking for inspiration for her art, based in nature and our natural surroundings. On noticing the amount of waste filling her natural areas, she decided she had to reflect it in her works.

For her latest project, Mariah is looking at both the problem of wasteful littering and the way that art itself can be wasteful in materials, taking the dropped items that fill her natural spaces and painting them to reflect the place in which they were left.

Applying paint to create her masterpieces, Mariah has collected trash (垃圾) from different mountains and parks. “I’ve been considering my relationship with art and the large amount of waste it can produce,” says Mariah. “I wanted to find ways I can confirm art and its important purpose by working with recycled materials found in landscape environments.”

“Since the 100th anniversary of the National Park Service, I’ve especially appreciated and been inspired by the natural beauty the parks offer, and found how easily we can take these precious places for granted. I seek to gather as much trash as possible, sculpt it into a canvas (画布), and paint the scene where the trash originated onto the trash itself,” says Mariah.

As well as through this project, Mariah has explored nature in her art in various different ways and through exhibitions. Mariah’s work might not solve the litter problem, but it’s just another way that we can get people talking about the problem and the ways we can prevent it from growing any larger.

7 . Chicago is considering firm measures to prevent the Asian carp,a giant fish native to the Far East, from coming into North America’s Great Lakes in large numbers. Such a move could cost up to$18bn, a heavy economic burden to the city.

This species, more than a metre in length, was originally introduced to southern US states three decades ago to control weeds in sewage (污水) treatment plants. But they escaped into the Mississippi River and increased in number quickly, making their way north towards the Great Lakes and threatening the native fish species along the way.

“Dozens of them will often leap out of the water as boats approach.’’ Michael Beecham，a local environmental expert, described how frightening the scene was. “I’ve gone down the river and seen these fish jump up and hit me in the face. It is a big problem for our native species.” he said.

A meeting has been organized to find a technological solution to the carp problem, one of which involves blocking parts of Chicago’s canal system. Listening at the meeting was John Goss, who was worried about the effect that having barriers in the canal system would have on industry. “It would certainly increase the cost of transportation,” he told. “It is currently very cheap and efficient to bring materials and finished goods down the Chicago ship canal.’’

Another cheaper option is to eat the fish out of existence. Dirk Fucik is selling carp burger(鲤鱼汉堡包) at his fish shop not far from downtown Chicago. He thinks the carps are a great resource. “To catch it and throw it away is a waste,” he says. “Eating them helps solve the problem and also provides jobs.” But the idea has not yet caught on．So far, he is the only person in Chicago selling carp burgers.

8 . Just a year ago, the colors were bright under the waves. Now it’s gray — the Maldivian reef is dead. The coral is killed by the pressure of rising temperatures.

Coral reefs are areas underwater where small creatures live. The coral is hard material formed on the bottom of the sea by the skeletons of those creatures. But the world has lost about half its coral reefs in the last 30 years. Scientists are working to prevent their destruction. Due to global warming, over 90 percent of corals are expected to die by 2050. “To lose coral reefs is to fundamentally undermine the health of a very large proportion of the human race,” said Ruth Gates, director of the Hawaii Institute of Marine Biology.

Why are coral reefs important? Coral reefs support a fourth of all marine species, as well as half a billion people worldwide. They serve as barriers to protect coastlines from the storms. They provide billions of dollars from tourism, fishing and other trade. They are also used in medical research for cures for diseases. “Everyone should be concerned,” said biologist Ove Guldberg at Australia’s University of Queensland. “This is not just some distant dive destination. This is the basic structure of the ecosystem we depend on.”

The ocean is getting warmer. A rising temperature of just one to two degree Celsius can force coral to expel the algae (驱逐海藻) that live there. This leaves their white skeletons uncovered. It is a process called “bleaching”. Sixteen percent of the world’s corals died of bleaching in 1998. The problem has become much worse in recent years.

“We’ve lost 50 percent of the reefs, but that means we still have 50 percent left,” said Ruth Gates, who is working in Hawaii to breed corals that can better withstand increasing temperatures. She is also trying to “train” corals to survive rising temperatures. Gates says it is time to start “thinking outside the box”— find creative ways to help them.

High on the Qinghai-Tibet Plateau     1     (lie) China’s “water tower” Sanjiangyuan. It is home to the headwaters of China’s three rivers: the Yellow River, Yangtze River, and Lancang (Mekong) River. The three rivers     2     provide water for about half the population of China play an important role. However, human activities are putting this ecosystem     3     risk.

In 2016, the Chinese government established Sanjiangyuan National Park in Qinghai province. The park,     4     (plan) to open in 2020, has increased the area’s green coverage and attracted more wildlife. The local government has also made great effort to improve biological diversity. The success of Sanjiangyuan will mark the start of a     5     (green) future.

With Sanjiangyuan     6     (take) the lead, nine other regions in China     7     (choose) by a field conservation station to carry out projects over the past three years,     8     will form a national park system together. The idea of a national park system is still new in China, but     9     (it) realization is urgent. After all,     10     (build) an ecological civilization bears great importance in the development and progress of human civilization.

10 . Bornholm is a Danish island in the southern part of the Baltic Sea. At only 588 square kilometers, the island is home to about 40,000 people and welcomes around 600,000 visitors each year. The island is known for its sunny weather, round churches and rocky sea cliffs. But soon it hopes to make history for its lack of trash (垃圾).

Bornholm's only waste incineration (焚烧) plant is on its last legs, so instead of replacing it, the island has come up with another plan. "In 2032 there'll be no more waste on Bornholm," the island's waste management company announced. "All unwanted items are resources that can be recycled to the benefit of the entire community. "

The government doesn't yet know all the specifics of how the plan will work, but officials have laid out a basic outline. For example, they fancy citizens sorting waste into easily recyclable items such as metal, plastic, glass, paper and cardboard, and then plan to add new items such as fishing nets, insulation materials and more plastics to the recycling system. Organic waste, as well as garden and park waste, will be changed into energy, and the nutrient-rich waste from energy recovery will be used as fertilizer in fields, gardens and parks on the island.

Residents will be encouraged to make use of the sharing economy, lending and borrowing goods and services. They'll reuse everything from furniture to children's clothing, and businesses will repair a large number of items from bicycles to kitchen appliances. And elementary school students will be educated as "resource heroes" with practical, hands-on lessons about waste, resources, the environment and nature.

"Yet, in the waste area we were falling behind, so it was important for us to move ahead," Anne Thomas, the deputy mayor of Bornholm, tells National Geographic.