触发全球降温

Strange as it may appear,

可见其中的奇怪之处

it seems this warm current is what tipped the planet into an ice age.

海洋暖流是地球进入冰河世纪的提示

Its warm waters brought more moisture to the cold northern regions of the planet

如果暖水带来更多的蒸汽 给地球寒冷的北部地区

so more snow fell, and ice began to build up.

这样会下更多雪

Slowly the Northern Hemisphere iced over,

北半球将会缓慢的被冰雪覆盖

triggering a global cooling.

触发全球降温

In the last million years,

在过去一百万年间

the ice has advanced and retreated 10 times in a cycle,

冰进攻和撤退，超过十次循环

aided by small changes in the Earth's orbit.

由地球轨道的细微变化导致

Although a few million years is just the blink of an eye in the planet's life,

对于地球生命来说数百万年不过是弹指一挥

this recent ice age has had an extraordinary influence on our world, and on us.

最近这次冰河世纪对于我们的世界，对于我们的确有特别的影响

It changed the climate across the planet.

我们发现，它改变了地球的气候

In doing so, it helped drive human evolution.

它的所作所为，推动了人类进化

Most obviously, it physically carved much of the world we know today.

雕刻了我们今天熟知的许多标志性景观

重点讲解

1、build up

（使）积聚；（使）逐渐增加

The regime built up the largest army in Africa.

该政权逐渐建立起一支非洲规模最大的军队。

The collection has been built up over the last seventeen years.

在过去的17年中，收藏的规模不断扩大。

增强…的体质；建立…的信心

Build her up with kindness and a sympathetic ear.

用友善和富有同情心的倾听来重拾她的信心。

Dr. Johnson and I have been trying to build him up physically.

约翰逊医生和我一直试图增强他的体质。

吹捧；抬举

The media will report on it and the tabloids will build it up.

媒体会报道此事，小报则会大肆吹捧。

Historians built him up as the champion of parliament.

历史学家把他誉为议会的捍卫者。

2、trigger

(枪的)扳机

A man pointed a gun at them and pulled the trigger.

一名男子拿枪指着他们，接着扣动了扳机。

引爆;启动;触发

The thieves must have deliberately triggered the alarm and hidden inside the house.

盗贼肯定是故意触发了报警器，然后躲在房子里。

The one thousand pound bomb was triggered by a wire.

那颗重达 1,000 磅的炸弹是由一根导线引爆的。

引起;发动;促使

the incident which triggered the outbreak of the First World War.

导致第一次世界大战爆发的事件

The current recession was triggered by a slump in consumer spending

目前的经济衰退是由消费支出骤跌引起的。