听力文本

Botos are highly social, and in the breeding season, there is stiff competition for mates.
亚马逊江豚是高度社会型动物。在繁殖季节，会有一场激烈的求偶竞赛
The males hold court in a unique way.
雄江豚会以独特的方式向雌江豚示爱
They pick up rocks in their jaws and flaunt them to their attending females.
它们用长嘴捡起石块，然后向自己的“心上人”炫耀。
Maybe each male is trying to show how strong and dexterous he is
这或许是雄江豚展示自己强壮身体和敏捷身手的一种方式
and that he therefore is the best father a female could have for her young.
以此来证明自己将是最好的父亲，雌江豚为了孩子就应该选它

Successful displays lead to mating.
求爱成功后，它们便开始交配
Even for giant rivers like the Amazon,
即使像亚马逊河这般巨大的江河
the journey to the sea is not always smooth or uninterrupted.
流向大海的过程也并非都是平缓连续的
Iguagu Falls, on the border of Brazil and Argentina,
位于巴西和阿根廷边境的伊瓜苏瀑布
is one of the widest waterfalls in the world, 1.5 miles across.
是世界上最宽的瀑布之一，宽幅达1.5英里。
In flood, 30 million litres of water spill over every second.
瀑布每秒的水流量达到3000万立方米。

词汇解析

1.on the border of 在…的边界上
Ferguson recruited 302 mainly Hispanic youth between the ages of 10 and 14 years, from a small Hispanic-majority city population on the border of Mexico, as part of a larger study of youth violence.
弗格森从墨西哥边境的一个主要由拉丁裔人口构成的小城市中选取了302位10-14岁的青少年，主要是拉丁裔，这是一个较大的关于青少年暴力研究的一部分。

2.spill over 溢出；形成
And how did that spill over to Asia?
粮食危机是怎样蔓延到亚洲的?

视频及简介

淡水是我们最宝贵的资源，它决定了地球上生命的分布。同河流一起，从高高的山峰一路而降，直向大海，观看壮观的瀑布，在大峡谷里飞翔，在世界上最深的湖泊的冰雪下面探索野生的生命，见证动物行为的独特的、生动的一面：水獭和泽鳄将一决胜负。