英语听力：自然百科 地球大迁徙

They're born to move, to move or die, forging ahead against terrifying odds¹, navigating² the first of millions of miles, spanning continents on fledgling wings, clattering³ ever onwards. 

他们天生就要迁徙，不迁徙即是选择了死亡。与可怕的对手周旋，它们一次要走数百万英里，羽翼未丰的翅膀振翅而飞跨越大洲。

Right now, our planet is on the march, on the wing, on the run, and these are the tales of its creatures, born into the most moving stories on earth, the stories of the great migrations⁴.

现在，我们的星球也在迁徙。在空中翱翔，在地面上奔袭。这是生物们的故事，地球上诞生的最动人的故事，这是大迁移的故事。

Life on earth is hard, perhaps nowhere harder than here and now. Every year, a timeless drama plays out on the Mara River. The elders have been through this many times. They must remember what awaits them. Their young know only the pervasive⁵ smell of fear, the instinct to stay close. 

地球上的生命大多是艰难的，也许没有比现在更艰难的。每一年，在Mara河都要上演一出永恒的戏剧。老辈们已经经历许多遍。他们必须记住在等待着他们的是什么。年轻人则嗅到了恐惧的感觉，本能地待在一起。

But they must press on.

但是他们必须坚持下去。

1 odds   

n.让步，机率，可能性，比率；胜败优劣之别

参考例句：

• The odds are 5 to 1 that she will win.她获胜的机会是五比一。
• Do you know the odds of winning the lottery once?你知道赢得一次彩票的几率多大吗？

2 navigating   

v.给（船舶、飞机等）引航，导航( navigate的现在分词 )；（从海上、空中等）横越；横渡；飞跃

参考例句：

• These can also be very useful when navigating time-based documents, such as video and audio. 它对于和时间有关的文档非常有用，比如视频和音频文档。 来自About Face 3交互设计精髓
• Vehicles slowed to a crawl on city roads, navigating slushy snow. 汽车在市区路上行驶缓慢，穿越泥泞的雪地。 来自互联网

3 clattering   

发出咔哒声（clatter的现在分词形式）

参考例句：

• Typewriters keep clattering away. 打字机在不停地嗒嗒作响。
• The typewriter was clattering away. 打字机啪嗒啪嗒地响着。

4 migrations   

n.迁移，移居( migration的名词复数 )

参考例句：

• It foundered during the turmoils accompanying the Great Migrations. 它在随着民族大迁徙而出现的混乱中崩溃。 来自辞典例句
• Birds also have built-in timepieces which send them off on fall and spring migrations. 鸟类也有天生的时间感应器指导它们秋春迁移。 来自互联网

5 pervasive   

adj.普遍的；遍布的，(到处)弥漫的；渗透性的

参考例句：

• It is the most pervasive compound on earth.它是地球上最普遍的化合物。
• The adverse health effects of car exhaust are pervasive and difficult to measure.汽车尾气对人类健康所构成的有害影响是普遍的，并且难以估算。