China’s first overpass for wildlife migration has already come into use. Lying over the     1     (new) constructed National Highway 216, the bridge is able to link animal habitats     2     (separate) by the road.

The national highway     3     (design) with the environmental protection as a top priority. Based on years of     4     (science) observation of wildlife migration in the region, the bridge was built with the purpose of reducing the highway’s effect     5     the animals. The wildlife overpasses and underpasses let animals     6     (cross) over or under busy roadways safely and allow them to use     7     (they)customary paths, which would otherwise be blocked. Those passageways, with     8     total length of 59 kilometers, enable antelopes and other animals to go across the railway freely.

So far, China     9     (put) great effort into achieving harmonious coexistence between human development and the protection of wildlife. The Qinghai—Tibet Railway,     10     is the world’s highest railroad, has 33 underpasses for the migrating animals.

When you take a walk in any of     1     cities in the west, you often see a lot of people walking with dogs. It is still true that the dog is the most useful and faithful animal in the world. But     2     reasons why people keep     3     dog have changed. In the old days, people used to train dogs to protect themselves against the attacks by other beasts. And later they came to realize that the dog was not only useful but willing to obey its master. For example, when people used dogs for hunting the dogs would not eat what they caught without permission. But now people in the city need not protect themselves against attacks of animals. Why do they keep dogs, then? Some people keep dogs to protect themselves from robbery, but     4     most important reason is for companionship. For a child, a dog is his best friend when he has no friends to play with; for young couples, a dog is their child when they have no children. So     5     main reason why people keep dogs has changed from protection to friendship.