In Sarek National Park, I wake up to the sound of the wind buffeting the cloth of my tent.     1     (stand) at the edge of the mountain, I find     2     (branch)of the Rapa River flowing through the valley below. Sarek’s mountains used to     3     (cover) by vast sheets of ice. Around 9,000 years ago, this ice     4     (melt), with about 100 glaciers     5     (leave) behind. Soon after, reindeer began to arrive. Following the reindeer     6     (be) the Sami people, who made this territory their home. In 1909, to keep the land’s natural state, the government made Sarek a national park.

For hundreds of years, the Sami lived off reindeer. With reindeer on the move, the Sami would pick     7     their tents and accompany them. Today, most Sami have houses in villages near Sarek and live     8     modern life. But every spring, a small number of Sami still follow their reindeer into the valleys of Sarek,     9     they live in tents and enjoy their traditions. Nothing could be     10     (good) than breathing the fresh air and enjoying this great adventure in such a beautiful and wild place.

The five interlocked Olympic rings have become fairly familiar at this point. But do you know what they mean and the story behind their    1    (create)?

The 1912 Olympic Games, held in Sweden, were the first to include athletes from    2    were then considered the five continents: Africa, Asia, Europe, Oceania, and America.    3     (inspire) by what had become a    4    (true) global event, Coubertin designed the symbol of the Games: the Olympic rings. Since 1920, the Olympic rings    5    (use) in every summer and winter Games.

Given what we know about colors and their many symbolic    6    (mean), it seems like it’d be safe to assume that each color featured in the Olympic rings would stand     7    something specific, like a continent.    8    in reality, that’s not the case at all. Coubertin    9    (choose) the six official Olympic colors——blue, yellow, black, green, red and white (featured in the background)——because when he introduced the symbol in 1913, every single flag of the nations     10    (participate) in the games could be reproduced using the colors in the Olympic symbol. Or, in his own words: “The six colors thus combined reproduce those of all nations without exception.”

6 . It is sometimes thought that the longing for material goods, the need to buy things, is a relatively modern invention.     1     Trade or shopping is certainly an ancient desire, and existed before our ancestors invented writing, laws, cities or farming, even before they used metal to make tools.

Humans are born to trade.     2     Evidence from hunter-gatherers suggests that the exchange of food and other necessary things comes naturally, as well as the ability to keep a record of the credits involved. And once trade begins, the benefits are hard to resist.

Ancient local coastal people in northern Australia traded fish hooks, along a chain of trading partners, with people living 400 miles inland, who cut and polished local stone to make axes (斧子).     3     Finally, both groups of “producers”, by concentrating on things they could produce and exchanging them for other things they needed, benefited as a result.

Trade in the necessities of life, such as food and simple tools, is not really surprising, considering the link between these basic items and survival. What is surprising, though, is that our taste for unnecessary expensive objects also goes back a long way.

In South Africa, 100,000-year-old decorative dyes (染料) have been found in an area where none were produced.     4     Small round pieces of glass 76,000 years old were also found at the same place. The earliest jewellery known to us were not just random findings — they were grouped together in size and had holes like those used for threading onto a necklace.

Archaeologists argue that trade prepared the way for the complex societies in which we live today.     5     However, their modern equivalents — fast cars and expensive clothes — hold the same attraction for us as “trade goods” did for people 100,000 years ago.

Dujiangyan is the oldest man-made water system in the world, and a wonder in the development of Chinese science.     1    (build) over 2, 200 years ago in what is now Sichuan Province in Southwest China, this amazing engineering     2    (achieve) is still used today.

In ancient times, the region in which Dujiangyan now stands     3    (suffer) from regular floods caused by overflow from the Minjiang River.     4    (help) the victims of the flooding, Li Bing, the region governor, together with his son, decided to find a solution. Li designed a series of channels built at different levels along Mount Yulei that would take away the floodwater while leaving the river flowing naturally.     5    (good) still, the extra water could be directed to the dry Chengdu Plain, making     6     suitable for farming.

Once the system was finished, no more floods occurred and the people were able to live     7    (peaceful). Today, Dujiangyan is admired by scientists from around the world because of one feature. Unlike modern dams     8     the water is blocked with a huge wall, Dujiangyan still lets water flow through the Minjiang River naturally,     9     (enable) ecosystem(生态系统) and fish populations to exist     10     harmony.