Arctic foxes live on the land and sea ice within the Arctic Circle,     1     the sun never rises to give warmth and light from October to February. Luckily, their long, fluffy tails act like a blanket to keep warm when they    2     (wrap) the tail around their body to sleep. Their feet also have a layer of thick fur,     3     helps cover footsteps. And their white coats make it difficult for predators such as    4     (wolf), polar bears, and golden eagles to spot them among the ice and snow.

For those consuming Asian food, using chopsticks     1    (be) almost second nature. About 20 to 33 percent of people in the world use chopsticks     2     a daily basis. Not all of those are disposable (一次性的),     3     no doubt many are.

Felix Böck, a student at the University of British Columbia, was eager to find a way to recycle wood from construction projects, and he had a particular interest in bamboo. One day he found a drawer in his friend’s house     4    (fill) with disposable bamboo chopsticks, and an idea hit him.

He decided to give     5     second life to disposable chopsticks by making them into home     6    (decoration) or other accessories (配件). He told the idea to restaurant owners,     7    (convince) them to install recycling bins in their restaurants. He cleaned the chopsticks, pressed them into square pieces and coated them with glue. The square pieces were then     8    (creative) arranged into household and office products. Böck’s company, called Chop Value, has repurposed chopsticks into desktops, cutting boards and even table games.

Since 2016 when the company     9    (found), Chop Value has rescued billions of chopsticks from landfills. Instead of an economy of the typical take-make-dispose model, Chop Value seeks to create one     10     transforms waste into a usable resource.

Xiechi Lake, also known as Yuncheng Salt Lake in China’s Shanxi Province,     1     (become) popular on social media websites in the past few years.

Now, China wants to transform that online     2     (popular) into real-life tourism. “As the Chinese ‘Dead Sea’, floating here is     3     unforgettable experience, and one you can’t find anywhere else,” reads a tourism advertisement     4     (sponsor) by the Yuncheng Salt Lake Tourism Development Company. Yuncheng Salt Lake is a sulfate (硫酸盐) lake. “If the sulfate in your water is greater than the calcium (钙), all the calcium is used up,     5     leaves you with large amounts of sulfate and you have a sulfate lake,” explains geography professor Bernie Owen. Xiechi is also a “closed basin” lake,     6     (mean) it doesn’t flow out to a river or ocean, which explains how its salt content stays so high. It is possible for salt lakes to freeze over, although not as     7     (quick) as other lakes — after all, think about what happens when we spread salt over icy roads. Saltwater freezes at     8    (low) temperatures than fresh water.

In an effort     9     (boost) Xiechi Lake’s international profile, China is reportedly taking steps to get it recognized     10     a UNESCO World Heritage site.

In every photo from our family vacation to Washington, D.C., I was showing off the souvenir I picked out at the Smithsonian’s National Zoo — a white, oversize, cotton sweatshirt with pandas     1     (dance) on the front.

Nearly 30 years later I found myself among     2     pool of photojournalists and video crews packed into the panda enclosure(围场), covering a small cub(幼兽) named Bei Bei for National Geographic.

After the photographs of Bei Bei     3     (publish), my editor suggested I ask zoo administrators if I could return periodically     4     (document) the first year of the cub’s life. They said yes.

On that first day with Bei Bei, I felt a little thrill as a zoo staffer took me down a quiet path to the back of the panda enclosure     5     the panda’s keepers were waiting. They introduced     6     (they), handed me shoe coverings and a mask, and led me through a series of gates and     7     (eventual) to Bei Bei.

Soon I was making regular     8     (stop) at the zoo to record the baby panda’s transformation. My kids had never been     9     (interested) in my job than when I was on the Bei Bei beat. When I mentioned the project     10     friends and neighbors, they would light up in ways I’d never seen. It turned out that everyone loved pandas.

Over the past few years, the interest in exploring Mars has grown, with some important     1     (discovery) about it. They raise further questions about the past atmosphere of Mars and scientists ultimately want to know whether or not it was     2     (suit) for life.

Images taken by the European Space Agency’s Mars Express satellite show the marks that     3     ancient network of rivers left on the     4     (planet) surface. The valleys formed as they would on earth,     5     a strong flow of water carving its way through the landscape.

    6     is less clear is where the water came from. Due to a lack of knowledge about the past climate of Mars, scientists cannot tell whether it came from melting glaciers (冰川), groundwater     7     something unheard of, though some researchers are doubtful whether liquid water was responsible for the marks     8     (see) by the satellite. They say other materials such as sand or dust can flow like a liquid and produce similar results.

Mars formed more than 4.5 billion years ago and there is no liquid water on the surface of it today. But scientists generally believe it     9     (go) through an early wet and warm era that ended after 1.5 billion to 2.5 billion years,     10     (leave) the planet extremely dry and cold.

Beijing is a city that straddles(跨越)the divide between the ancient and the modern. It is home     1     more than 3,000 years of fascinating history, and a place     2     fully embraces the fast-paced development of modern life, with high-rise 21st-century architectural wonders standing side by side with cultural relics of the past.

This integration of styles     3     (be) strikingly typical at Zhihua Temple, built in 1444 during the rule of emperor Zhengtong. Though much smaller now than at its peak of 20,000 square meters, the temple is a somewhat     4     (hide) treasure.

    5     (remarkable), the temple museum offers a collection of remains and statues. You might even forget you’re in the 2lst century, if not for the smooth curve of the modern Galaxy Soho building looming over the mythical beasts(神兽)seated on the ridges(屋脊)of the temple roofs.

Yet     6     they belong to completely different     7     (era),   appearances and purposes, they are both equally representative of this city. Seeing the two together is a perfect example of the idea of how respecting our history, while still     8     (look)to the future, can create a truly unique cityscape.

The development of this city, which is carefully designed     9     (protect)the past while embracing the modern world,    10     (mean)there is always something new to discover here, and I could be photographing Beijing for the next 50 years and still not have scratched the surface, which is part of its beauty.

The first domestic chickens we have found lived no earlier than 3,670 years ago, suggesting they have a far shorter history than we thought. These birds don’t seem to have been raised for their meat,     1     (make) it unclear what drove domestication. The chickens alive today descend from a wild bird native to South-East Asia     2     (call) the red jungle fowl, but exactly     3     domestication occurred was unclear. Some researchers have estimated that the first domestic chicken lived more than 6000 years ago, while others claim     4     (find) chicken bones at 10,000-year-old sites.     5     analysis by Ophelie Lebrasseur at the Centre for Anthropobiology and Genomics of Toulouse in France and her team concludes that the     6     (early) clear evidence of domestic chickens appeared between 1,650 BC and 1,250 BC at a site called Ban Non Wat in central Thailand. Not only     7     (be) chicken bones superabundant at the site, but there are signs that people were buried with the birds,     8     Lebrasseur says makes a domestic relationship clear. Lebrasseur and her team suspect chicken domestication might have been triggered by the       9     (appear) of cereal fanning in South-East Asia. “This created a more open, less tree-covered environment, which is actually an environment where red jungle fowl thrive,” she says, “And they could have fed     10     the waste from human societies.”

The Lion Rock mountain stands not only as one of the most famous scenic spots in Hong Kong,     1     has become a spiritual symbol representing the persistent efforts of ordinary Hong Kong people     2     (live) a better life.

The Lion Rock spirit has also     3     (deep) touched those outside Hong Kong, such as Cui Xiaodong,     4     ink artist and director of the Yan Huang Art Museum in Beijing. “The mountain stands like a giant, symbolizing the industrious and persistent spirit which, over the past decades,     5     (pull) people in Hong Kong together through hard times. It is a recollection of the youth and vigor (活力) of a generation of people in Hong Kong     6     struggled to make the city what it is today.” he says.

Cui created Lion Rock in Hong Kong, a colored ink painting. In his painting, Cui depicts (描绘) the cliffs of the Lion Rock, surrounded by blooming trees and     7     (overlook) the city’s skyscrapers. Made earlier this year, the painting is now     8     show at Greater Bay Area in the Eyes of Artists, a display marking the 25th anniversary of the Hong Kong Special Administrative Region. The     9     (exhibit) displayed there hail (向……致敬) the ecological diversity of the area and also presents to the audience     10     (success) reformative accomplishments since 1997.