英语听力：自然百科 探索世界奥秘之Wild Africa - Deserts(浩瀚沙漠) Unit14

（单词翻译）

The Arabian camel--not even a native , was domesticated¹ in the deserts of Asia and brought to Northern Africa as a means of transport. In the past , Tuareg nomads² used camels to move slaves, gold and ivory between West Africa and the Mediterranean³. Today their caravans⁴ still trade in salts, dates and millet⁵.

The Sahara has long been a frontier between Asia and Africa. But there are European pioneers here too--red foxes, which scrape a living 

on the Northern fringes of this vast desert.

Though much of the Sahara is uninhabitable, there are a few special places where life can thrive. The Ennedi Mountains in Chad harness a little more moisture from clouds than lower-lying areas enough to support tiny pockets of Savanna⁶. Here rock hyraxes survive on the leaves of acacia trees, a scene more typical of the African plains. These green islands are relics⁷ of an older world, one which is slowly vanishing with the march of the desert sands.

The Sahara , as we know it today, is only 2, 000 years old, the product of a rapidly drying climate in North Africa. But our ancestors also had a hand in this change. By over-cultivating marginal lands, and intensively grazing livestock⁸. Before, things were very different. Try to imagine this land flooded by the ocean, swathed in forest and savannah, swept by mighty⁹ rivers.

Ennedi Gorge¹⁰ once fed a vast tributary¹¹ of the Nile. Today all that remains¹² are a few precious pools, crucial watering holes for passing caravans of camels. In just 10 minutes of drinking , these remarkable¹³ animals can put on a third of their body weight in water. It's enough to carry them for well over 100 kilometers to the next oasis¹⁴.

Tuareg:西撒哈拉和中撒哈拉的柏柏尔人

trade in :a method of buying something new by giving an item you own as part of the payment for it 抵价购物

scrape a living :to only just earn enough money to provide yourself with food, clothing and a place to live 勉强够维持生活

hyraxes: a kind of animal 蹄兔

have a hand in: 干予, 参与, 插手