VOA慢速英语:From Ancient Farmers, Lessons for Today's Amazon

短语讲解：

1.  But the Amazon is disappearing at the rate of about eighthundred thousand hectares a year.

at the rate of 以……速度或比率
例句： The train was going at the rate of 95 kilometres an hour. 
火车正以每小时９５公里的速度前进。 

2.  The study looks at the pre-Columbian period.

look at 注视；察看
例句：Look at the map, please.
请看这张地图。

3. Christopher Columbus and other European explorers beganarriving in the Americas in the late fourteen hundreds.

arrive in 到达某地(大地方)
例句：She arrived in this country ten years ago.
她十年前到达这个国家。

4. When land is not being used for farming, periods without fireare most effective in rebuilding soil organic matter andpreserving soil structure.

be used for 被用于
例句：Allocate a room to be used for storage. 
指定一间房用来贮藏 

5. Experts say at current rates, more than half of the Amazon'stropical rainforest could be gone by twenty-thirty.

more than 大于，不只
例句：True friendship is worth more than money. 
真正的友谊比金钱更有价值。