5 . The Silk Road is the name of different roads that long ago connected Europe, Africa and Asia. People reached these different places along these roads. Scientists believe people began to travel the Silk Road about 3000 years ago. By the time the Chinese silk trade became important in the world, the Silk Road covered almost 6500 kilometers. It spread from Rome to China, which is from the West to the Far East.

Traders travelling along the Silk Road carried silk, of course. They also carried and traded spices (香料), cloth, valuable stones and gold.

There is a famous old story along the old road. It is said that Roman soldiers travelled through central Asia. They started to live somewhere near the ancient Chinese village of Liqian. Sortie of these Romans married local Chinese women and the story of blue-eyed villages of China was started.

During its busiest period, the Silk Road allowed people from many different cultures and countries to meet each other and mix. The Silk Road allowed the sharing of valuable goods and new ideas. These included people and trading goods from the Mediterranean, Persian, Magyar, Armenian, Bactrian, Indian and Chinese areas. All these peoples travelled the Silk Road, and they shared goods, stories, languages, and cultures.

In modern times, the old Silk Road routes (路线) are still used, but now they are crossed by trains instead of camels and horses. There is even a Silk Route Museum in Jiuquan in China. It has over 35,000, objects from all along the Silk Road. In this way, China protects the history of many countries and peoples.

The heat wave that broke high temperature records in five European countries a week ago is now over Greenland,     1     (cause) the surface of the island’s vast ice sheet to melt at near-record levels and a huge     2     (lose) of ice in the Arctic. On Wednesday alone, more than 10 billion tons of ice was lost to the oceans by surface melt, which is equal to about 4,000,000 Olympic-sized swimming pools.

Melting     3     (increase) in recent decades because of climate change and has been decreasing accumulation from snow. Previously, during the 1970s and the 1980s, Greenland lost an average of 50 billion tons of ice each year. From 2010 to 2018,that figure shot up to 290 billion Tons     4     (annual). Next summer, the extent of the melt could surpass (超过) the record set in 2012,    5     about 97% of the ice sheet’s surface began to melt, NASA-JPL Caltech reported at the time.

Greenland, the world’s     6       (large) island, lies between the Atlantic and Arctic oceans, with 82 per cent of its surface covered in ice.     7     June 2019 study by scientists in the U.S. and Denmark said melting ice in Greenland alone would add between 5 and 33 centimeters to the rising     8     (globe) sea levels by the year 2100.     9     all the ice in Greenland melted, which would take centuries, the world’s oceans would rise     10     7.2 meter.

7 . I strongly believe that individual actions make a difference to our environment. I’ve been a vegetarian for more than two decades, choose to be child-free partially because I can’t justify my genes’ importance over the shocking amount of resources needed for raising another American, and haven’t owned a car in four years. Those things, over time, will absolutely reduce my impact on our beautiful world, and the more people do them, the greater the impact is.

But it’s not nearly enough.

While I will continue to do my part to fight climate change, I have to wonder why there isn’t an equal effort by those who have the biggest impact. According to a recent report, 71% of greenhouse gases are produced by just 100 companies. Surely, working to minimize their emissions (排放物) will do far more, much faster than me talking people’s ears off on Facebook about eating less meat. After all, I have been doing that kind of work for 20 years now, and we are still headed towards climate disaster.

Why should so much of the solution to global warming be on the shoulders of individuals?

When President Kennedy decided we needed to beat the Russians to the moon landing, he didn’t encourage housewives to figure out bow to get there. He got the smartest and most talented people together to solve the challenges. NASA got us there, with lots of hard work and late nights, and also full encouragement and funding from the US government.

But this is not the case with climate change. Big companies are let off the hook while we take on the huge burden of dealing with the emissions of the biggest and most powerful. That strikes me as just plain unfair. The serious threats of climate change require an all-hand-on-deck response. Corporations need to do their part, because I can’t do it on my own.

9 . In habitats across the planet, animals periodically drop everything to walk, fly or swim to a new place. Some animals such as whales and geese learn migration paths by following their parents. Others, including small songbirds, gain the distance and direction of their migration within their genetic code. And some animals use a combination of genetics and culture to guide their migration.

Another group of migrators does not quite fit either model, and researchers have only recently started to figure out how they find their way. The Cory’s shearwater is an oceangoing seabird that migrates over the Atlantic every year. The young do not migrate with their parents, so culture cannot explain their journeys. And the exact paths vary wildly from individual to individual, making genetics equally unlikely.

Cory’s shearwaters are long-lived, rarely producing young successfully before age nine. This leaves an opening for learning and practice to develop their migration patterns. Researchers call this the “exploration-refinement”, and until now it has been hypothetical (假设的) because of difficulties in tracking migratory animals’ movements.

But a team of researchers has done that by attaching small geolocators to more than 150 of the birds aged four to nine. They found that younger birds traveled longer distances, for longer periods, and had more diverse paths than older birds. “We finally have evidence of the ‘exploration-refinement’ for migratory birds,” says Letizia Campioni, who led the study. Younger Cory’s shearwaters are able to fly just as fast as the adults——but they do not, suggesting that the young do more exploring, which gradually fades as they mature and settle into a preferred course.

“Although it may seem less efficient than other strategies, exploration refinement could be beneficial to birds and other organisms in a rapidly changing world due to unpredictable man-made changes,” says Barbara Frei. “It might be safer to repeat a behavior that was recently successful than to rely on patterns that were perfected long ago but might no longer be safe.”

10 . A five-­year-­old dog named Kelsey has been praised as a hero for helping to save the life of her owner who slipped in the snow and broke his neck.

The man, Bob, was alone when he left his farmhouse on New Year’s Eve to collect firewood.Expecting a journey of only several meters, Bob was wearing just long johns (衬裤), a shirt and slippers when he went outside, although the temperature was around －4℃.

After the accident, he was unable to move in the snow. Fortunately, Kelsey came to his assistance.

“I was shouting for help, but my nearest neighbor is about 400 meters away, and it was 10:30 p. m.,” Bob explained. “By the next morning, my voice was gone and I couldn’t yell for help, but Kelsey didn’t stop barking.”

Kelsey’s companion kept him warm by lying on top of him. She licked his face and hands to keep him awake. “Kelsey kept barking but never left my side,” Bob recalled. “I knew I couldn’t give up and that it was my choice to stay alive.”

Bob spent 20 hours in the freezing cold. When he finally lost consciousness, his dog kept barking. Finally, hearing the barking, Bob’s neighbor discovered him at 6:30 p. m. on New Year’s Day and called the emergency services at once. When Bob arrived in hospital, his body temperature was below 21℃. However, doctors were surprised to find that he didn’t have any frostbite (冻疮). They believed it was because of Kelsey’s determination to keep him warm. Dr. Chaim Colen, the doctor who treated Bob, said, “His dog really saved him.He was very fortunate.”

Bob said he was very grateful to both Dr. Colen and his Kelsey. “They saved my life. They are truly heroes!”