混沌初开

This is a type of lightning

这是一种闪电

that doesn't strike down towards the ground

它们不直接袭击地表面

but instead reaches upwards within the mesosphere,

而是往上发射，高至中心层

30-50 miles high.

30到50英里高

We've seen the power of the atmosphere to shape the planet

我们看过大气的力量是怎样塑造星球

and create the weather,

和创造气候

but it's the relationship between the atmosphere and life

大气和生命的联系

that has made our planet unique in the solar system.

使我们的地球在太阳系中独一无二

To understand how this vital relationship evolved,

要明白这一重要的关系如何发生

you have to go back to the very beginning of Earth's long history.

得追溯到很久以前地球混沌初开时

The planet's atmosphere was created shortly after the Earth was formed

在地球刚形成不久大气圏就形成了

four and a half billion years ago.

四十六亿年前

The early Earth was probably highly volcanic.

早期地球充满火山

And for millions of years,

几百万年后

these volcanoes spewed out huge quantities of gas.

这些火山喷发出大量气体

Slowly these gases built up and created the atmosphere.

这些气体缓慢聚合创造了大气层

重点讲解

1、strike down

摧垮;使病倒;使丧命

Frank had been struck down by a massive heart attack.

弗兰克的身体已经被一场严重的心脏病拖垮了。

a great sporting hero, struck down at 49.

在 49 岁时因病逝世的一个了不起的体坛英雄人物

废止，取缔，终结(非法的法律或规定)

The Supreme Court today struck down a law that prevents criminals from profiting from books or movies about their crimes.

最高法院今天废止了一项关于禁止罪犯把其罪行写成书或拍成电影而从中牟利的法律。

2、unique

唯一的；独一无二的

Each person's signature is unique.

每个人的签名都是独一无二的。

The area has its own unique language, Catalan.

这个地区有自己单独的语言，加泰罗尼亚语。

独特的；无与伦比的

Brett's vocals are just unique.

布雷特的歌声无与伦比。

Kauffman was a woman of unique talent and determination.

考夫曼是一个有着超群才智和决断力的女子。

独有的；特有的

No one knows for sure why adolescence is unique to humans.

没有人确切地知道为什么只有人类才会经历青春期。

This interesting and charming creature is unique to Borneo.

这种有趣迷人的动物是婆罗洲独有的。

3、evolve

进化；演变

The bright plumage of many male birds has evolved to attract females.

很多雄鸟进化出鲜艳的羽毛是为了吸引雌鸟。

Maize evolved from a wild grass in Mexico.

玉米是从墨西哥的一种野生禾本植物进化而来的。

动词（使）逐步发展;（使）演化

a tiny airline which eventually evolved into Pakistan International Airlines.

最终发展成巴基斯坦国际航空公司的一家小型航空公司

Popular music evolved from folk songs.

流行音乐从民歌演变而来。