英语听力：自然百科 探索世界奥秘之Wild Africa - Deserts(浩瀚沙漠) Unit03（在线收听）

Pinning the ants to the hot sand surface, the spiders first cook them to death before dragging them under.

In the Namib, even the toughest animals struggle with the heat. Gemsbok trek to the crests of the highest dunes to seek relief in the breeze.

With no cloud cover, solar radiation blasting the desert is intense. The mid-day sand is so hot. It's like a bed of burning coals. The Namib quickstep. Over millions of years, you learn to keep your claws cool. Pushed by the wind, the dunes avalanche. The Namib's residents can't fight the tide.

Though the dunes are unstable, they provide a home for a remarkable creature. The trapdoor spider only builds its nest on the top of the steepest dunes. It's learned to do this because it has a very aggressive enemy, a wasp, which relentlessly scours the sand.

Though its eyesight is poor, the wasp has very sensitive hairs on its legs which can pick up the slightest scent of a spider. When it finds a nest, the wasp quickly works out how deep the burrow is. If it's shallow, the wasp starts digging for up to two hours. It's hard work against the slipping sand. 

words:

1.trek:艰辛跋涉

eg:The old man treked through the moutains.

2.quickstep:齐步,轻快步曲

3.avalanche:雪崩

4.scour:搜索,急速穿过

eg:scour the forest

scour the library for reference