2 . The Silk Road is arguably the most famous long-distance trade route of the ancient world. This passage connected Europe in the West with China in the East, and allowed the exchange of goods, technology, and ideas between the two civilizations. Although merchants could make huge profits travelling the road, it was not without risk.

The main Silk Road started in Chang’an (known today as Xi’an), the early Han capital. Travelers commencing their journey from this city could take a northern route that would take them across China’s northwestern provinces. After this, they would face the Gobi Desert, arguably the greatest danger of the Silk Road.

The Gobi Desert, the largest desert in Asia, consists mainly of rocky, hard earth. This feature made it easier for traders to travel across, compared to sandy deserts like the neighboring Taklamakan Desert. Like other deserts, the Gobi Desert is dry and hot, and therefore the biggest challenge travelers faced was obtaining enough water for themselves as well as for their camels.

So, rest stops were created along the route, allowing travelers to rest, eat and drink. These places also promoted the exchange of goods, and even ideas, amongst the travelers who stopped there. Usually, the rest stops were placed within a day’s journey of each other. In this way, travelers could avoid spending too much time in the desert, which would make them targets for robbers, another danger of the Silk Road.

Once through the Gobi Desert, travelers would continue their journey into Iran, Turkey, and finally Europe. While this part of the journey may have been less dangerous, it is not entirely without its perils (风险).

6 . To understand the effect of ice melting (融化) around the world we first have to understand what an ice sheet actually is. Covering 5.4 million square miles in Antarctica (南极洲) and 656,000 square miles in Greenland, an ice sheet is actually a huge land of ice from the Ice Age. These sheets form in areas where snow that falls in winter does not melt entirely over the summer. This ice, home to different species of animals, is now melting at a rate that cannot support the life it currently holds.

Many of these creatures rely on ice sheets as land for resting, hunting and protection, yet as the size decreases, they are forced out of their homeland in search of other land on which to live. Often this means journeys to search for food and an imbalanced ecosystem happens when different species are forced together onto the coast.

Since the 1990s, the deer population has dropped by 56 per cent—climate change has caused warmer temperatures over winter setting off rainfall instead of snow, which freezes more quickly underfoot and makes it harder to walk and search for food. In the summer, frozen layers of land melts and releases trapped diseases which bring death to animals. A similar situation has fallen on the polar bears who suffered a 40 per cent population loss between 2001—2010.

Quite apart from these problems, the threat of sea levels rising if the ice caps were to disappear is approaching. If the Greenland Ice Sheet melted, the sea level would rise around six meters, and if the Antarctic Ice Sheet melted, sea levels would rise by around 20 feet. As a matter of fact, sea levels have risen about eight inches since 1880, three of which we’ve gained over the last 25 years. This seemingly small amount has already caused dangerous flooding, loss of farmland and more deadly storms.

While we’re still a long way from losing the ice sheets all together, we’ve already lost too much and if we don’t take climate change seriously now, we will certainly hit the point of no return.

A park in Arouca, Portugal opened a new bridge. Though it's quite high，it's the     1     (long ) of the bridge that has set a record. It's the world's longest hanging bridge for walkers-over five football fields long.

It's a suspension (悬索桥) bridge,     2     means it hangs between two mountains without any supports underneath. The builders say the bridge was inspired by suspension bridges     3     (build) by the ancient Inca people in South America. It was started in May, 2018 and it took the builders over two years     4     (complete) the project.

But even though the bridge is     5     ( solid) made, it's still a little scary to walk on. At its highest point, the bridge is 175 meters off the ground. Far, far below     6    (be) the rushing river.

Arouca Geopark is well-known for its beautiful     7    (nature) scenery and the many outdoor activities that can     8    (do) there.

Now, the city of Arouca is hoping that the bridge will bring lots of tourists-and     9       (they) money-to the area. City leaders think the bridge could attract people     10     a lot of different reasons. Some might come for the scenery. Others might come to see the structure of the bridge. But perhaps most will come to enjoy the safe but scary experience of walking across.

8 . There are around 100 tribes(部落)that live in global isolation, mostly in South America and India. The Sentinelese have lived on one of the Andaman Islands in Eastern India for 60, 000 years. They protect their island by fighting against people from outside. Their language is different from any other known language. Another Andaman tribe is the Jarawa. In the past, they were independent and fought against anybody trying to make contact with them. But in 1998, the Indian government built a road across their land, and since then, they’ve had more contact with the outside world.

Some Amazon tribes avoid contact because of unhappy memories. The Mashco-Piro left their vegetable gardens after rubber companies killed most of their tribe at the beginning of the 20th century. Those who survived became nomadic(游牧的)and started hunting animals in the forest.

The Awa live in the Amazon forests ofBrazil. Out of 350 members, 100 have no contact with the outside world. They left their villages and adopted a nomadic lifestyle around 1850 to escape attacks by Europeans. In the following years, farmers in nearby communities started cutting the trees to expand their farmland. The Awa lost most of their hunting land. The few Amazon tribes that still exist are fighting to keep their traditional way of life.

Survival, an organization that fights for the rights of tribal people, says that uncontacted tribes are the most vulnerable(弱势的)humans on the planet and that’s why their environment should be unavailable to the rest of us. After years of pressure, the organization got Brazil’s government to clear non-natives from the Awa land. All non-Awa people are leaving so the tribe can get their forest back.

But some think it's impossible for tribes to stay isolated forever in a connected world. Contact will be made one day. So the question is：Whose choice should it be, ours or theirs?

A Beautiful Place in China

Now rewind this picture 1,839 years. You are in the same seat, only you are watching classical Greek entertainment.

The city of Athens is a fun mix of the old and the new, the classic and the modern. Often a little shop is located next to the ruins of a temple, which is only a block from a large, air-conditioned hotel. The great city of 2,500 years ago is still visible today.

Ruins are the most obvious sign of ancient Athens, and the most famous of these is the Acropolis(卫城). The Acropolis is a large hill that was the center of life in Athens. On its slopes were temples, monuments, and theaters. From the top, you can see how the urban area of Athens stretches out in every direction.

On the top of the Acropolis is the Parthenon. This was once a huge temple to Athena, the city’s patron. It was first completed in 432 B.C., but has been damaged and destroyed several times. However, visitors can still see the “tricks” used in building the Parthenon. The columns along the outside lean inward, and are slightly fatter in the middle. The temple is also higher in the middle than on the sides. All these effects make the Parthenon look perfectly straight from a distance.

Only a block away from the Acropolis is the neighborhood of Plaka. The area, with its little shops and restaurants, is very popular with both tourists and locals, and is an important part of modern Athenian culture. Many great thinkers, writers, and political leaders lived in ancient Athens. The ruins of their homes and favorite spots are scattered throughout the busy port city. The hill where St. Paul addressed early Christian Athenians is located near the Acropolis. Great thinkers such as Perikles and Demosthenes spoke to the civil assemblies held at the Pnyx Hill. Today the Pnyx is an open-air theater for light and sound shows.

Tourism is very important to people who live in modern-day Athens. Thousands of people come every year to see these ruins and to tour the many museums that house artifacts from ancient times. This provides many jobs and brings money into Athens, which helps the city pay for improvements. Athenians take pride in the accomplishments of their ancestors, and people from all around the world come to admire them. By looking around the city today, we can imagine what life was like in ancient Athens.