About 4,000 years ago,Bactrian camels were domesticated.

大约4000多年前人们驯化了双。

But it is the only source of water, so Bactrian camels eat it.

可是这是唯一水源，所以双只能吃雪。

So Ganbold and his twin-humped Bactrian camels must chase the snow towards the mountains where it lingers.

所以冈包勒德和他双须循着雪花，向着它们所属山赶去。

This extraordinary performance is a male Bactrian camel's way of attracting the attention of a passing female.

这种奇演是公双吸引路过母骆一种方式。

China is one of the main habitats for Bactrian camels in the world, but the ancestral home of camels is in North America, far away.

中国是世界上双主要栖息地之一但骆祖籍却在遥远北美洲。

The Macedonian troops who stayed in the city intermarried, and they became the Greco-Bactrian Kingdom, which flourished in Central Asia after Alexander's death.

留在城内马其顿军队与当地人通婚，成为希腊-巴克特里亚王国，亚历山大死后，该王国在中亚蓬勃发展。

Although Alexander's Bactrian wife, Roxana, was pregnant at the time of  his death, there was no viable heir, and Alexander's vast empire fell to infighting  among his generals.

尽管亚历山大双人妻子罗克珊娜在他去世时已怀孕，但没有合适继承人，亚历山大庞大帝国也陷入了将军们内斗。