铁矿石脉

It was this reaction that stopped the oxygen leaving the sea.

这反应就阻止了氧气离开大海

The rust fell to the bottom of the sea and it built up as layers.

铁锈沉入海底，层层堆积

And you can...Oh!

你可以…噢！

This is so hot. You can see these layers right here.

这太热了你能看到铁锈层就在那

I mean, this is metal, that's why it's so hot.

我是说，这是金属，所以非常热

You can see the layers in the fine colourful banding on this rock.

你可以看到这铁锈层有很漂亮的条纹

Here it's on a tiny scale, but on this cliff, it's on a massive scale.

这是一条细小的条纹在这悬崖上，有非常大的条纹

The layers of rust were laid down all across the world,

铁锈层在整个世界都有

eventually turning into seams of iron ore.

甚至变成铁矿石缝

All this iron ore, in fact, much of the iron ore mined across the world,

这些铁矿石实际上世界大部分铁矿石脉

only exists because very early life, stromatolites,

存在是因为早期生命，叠层石

started filling the seas with oxygen more than two billion years ago.

二十亿年前开始为海水输氧气

But that was just the very beginning of how oxygen changed our planet.

不过这是氧气改变我们星球最初始的情况

重点讲解

1、lay down

（通常指用完后）放下， 搁下

Daniel finished the article and laid the newspaper down on his desk.

丹尼尔看完文章后把报纸放在他的书桌上。

She laid down her knife and fork and pushed her plate away.

她放下刀叉，推开盘子。

规定；制定；颁布

The Companies Act lays down a set of minimum requirements.

《公司法》规定了一系列最低标准。

Taxis must conform to the rigorous standards laid down by the police.

出租车必须遵守警方的严格规定。

放下（武器）

The drug-traffickers have offered to lay down their arms.

毒贩们已同意放下武器。

2、band

（流行音乐）乐队，乐团

He was a drummer in a rock band.

他曾是一个摇滚乐团的鼓手。

Local bands provide music for dancing.

当地的乐队为跳舞伴乐。

（一）群；（一）帮；（一）伙

a small but growing band of Japanese companies taking their first steps into American publishing.

数量不多、但仍在增长的一批初次涉足美国出版业的日本公司

（用以加固或捆绑的）圈，箍

Surgeons placed a metal band around the knee cap to help it knit back together.

外科医生在膝盖骨上套了个金属箍以帮助其愈合。

a strong band of flat muscle tissue.

一圈坚韧的扁平肌肉组织

将…划分范围；把…分段

They appear to rule out some of the ideas that have been mentioned — banding the tax so higher earners would pay more.

他们看来要剔除其中提到的一些想法——如把税率分档，使收入越高，缴得越多。

a banding system based on property values.

基于财产价值的分级制