Tibetan antelopes live on the plains of Tibet, Xinjiang, and Qinghai.     1    (watch) them move slowly across the green grass, I     2    (strike) by their beauty. I’m also reminded of the danger they are in. They are being hunted, illegally, for their       3    (value) fur.

My guide is Zhaxi,     4     villager from Changtang. He works at the Changtang National Nature Reserve. The reserve is a shelter     5     the animals and plants of northwestern Tibet. To Zhaxi, the land is sacred and protecting the wildlife is a way of life. “We’re not trying       6    (save) the animals.” he says. “     7    (actual) , we’re trying to save     8    (us) .”

The 1980s and 1990s were bad times for the Tibetan antelope. The population dropped by more than 50 percent. Hunters were shooting antelopes to make profits. Their     9    (habitat) were becoming smaller     10     new roads and railways were built.

Scientists have discovered the world’s fastest ant. It is the Saharan silver ant. It runs     1     a speed of just over 3kph. The ant runs 108 times the     2     (long) of its own body every second. This is     3     (quick) than an Olympic 100-meter runner. The world’s fastest man, Usain Bolt, ran the 100 meters     4     (use) 4 strides (大步) a second while the Saharan silver ant uses up to 50 strides a second. The scientists say this much movement almost breaks the limits of     5     is physically possible for a living thing. Each of the ants’ feet makes contact with the ground for just seven milliseconds before they take     6     next stride.

The scientists said the Saharan silver ant runs so fast because it lives in the hot desert     7     the sand can reach temperatures of up to 60 degrees Celsius, so the ant desires     8     (spend) as little time as possible with its feet on the scorching ground. Another reason is that if the ants’ feet spend a longer time on the sand, they     9     (sink)a little and slow down. Professor Wolf told CNN, “We knew these ants would be fast, but nobody knew how fast     10     (exact), and how they would achieve that speed.”