题目内容：

    Seeing someone who seems to be walking on a cloud sounds like a dream. But this scene indeed exists --- and it isn't just in your head. It's a popular attraction in the South American country of Bolivia called the Salar de Uyuni. The area covers a large amount of white, glistening salt and runs across 10,582 kilometers of the Altiplano and you can even see it from space.

What's special about the Salar? This salt flat can create an endless natural mirror (镜子), which gives you an amazing experience. On a still day, a thin layer of water covering the salt changes the salt flat into "The World's Largest Mirror" reflecting the sky. Those who are lucky enough to see this natural wonder will tell you how difficult it is to find out the dividing line between the sky and land.

Some 40,000 years ago, water from the surrounding mountains gathered here and there were no outlets (出口) where the rainfall could flow out. So a huge lake was formed with natural salt inside. Over time, about 25,000 years ago, a rise in temperatures reduced the amount of rainfall in the area. The climate from wet to dry caused the water to slowly evaporate (蒸发). About 10,000 years ago, the body of water dried up and a deep layer of salt flat was left behind.

With about 10 billion tons  of salt lying around it, it's no surprise that salt production in the Salar is a big business. But the real treasure lies under the surface of the salt flat, where around 70% of the world's lithium (锂) reserves can be found. The lithium is used for powering mobile phones, laptops, electric cars and this resource could be of great value.

What is the Salar de Uyuni	●It's a place of 1. in the South American country of Bolivia. ●It is an area 2. with white and glistening salt. ●It runs across about 10,582 kilometers and can even be 3. from space.
What's special about the Salar de Uyuni?	●On a still day, the salt flat will 4. into "The World's Largest Mirror", which gives you a wonderful experience. ●If you are lucky enough to see it, you may find it difficult to tell 5. The sky ends and the land begins.
How did the Salar de Uyuni 6. ?	●40,000  years  ago,  the  surrounding  mountains 7. the water from flowing out and it became a huge lake. ●25,000 years ago, the climate changes 8. to the evaporation of the lake. ●10,000 years ago, the lake dried up, 9. behind a deep layer of salt.
What's under the Salar de Uyuni?	●70% of the world's lithium lies under the salt flat. ●Lithium can be used to power things 10. mobile phones, laptops and electric cars.