Why were redwood trees more prominent in the forests of North America millions of years ago?

They lived on the earth tens of millions of years ago, long before humans came into being

千百万年前它们（恐龙）就在地球上生活，比人类的出现要早得多

So how on earth have we worked out so much about animals that lived millions of years ago?

因此我们到底要怎么去了解数百万年以前的动物？

The energy which coal provides is the solar energy which was stored by plants millions of years ago.

煤提供的能量是千百万前的植物储存的太阳能。

Giant pandasare thought tohave originated in southwest China, millions of years ago,

大熊猫被认为在几百万年前起源于中国的西南部

Dinosaurs lived millions of years ago.

恐龙生活在数百万年前。

Cancer has probably existed ever since our first multicellular ancestors appeared on Earth hundreds of millions of years ago.

在我们最早的多细胞生物祖先于数亿年前在地球上出现时，癌症可能就已经存在。

The exhibition at the natural history museum includes fossils of amphibious creatures from millions of years ago.

自然历史博物馆的展览包括数百万年前水陆两栖动物的化石。

Mountains that we see here today aren't the mountains that were around millions of years ago.

我们今天在这里看到的山，与大约百万年前的山是不一样的。

The print of geological events that happened millions of years ago is the best pledge.

那些被亿万年的地质变迁雕琢过的印记，是我给你最好的信物。

Dinosaurs died out millions of years ago.

恐龙几百万年前灭绝了。

Coal was made by the rocks pressing on trees and plants which died millions of years ago.

煤产生于岩石对数百万年前枯死的树木和其他植物的挤压。

Oil is a fossil fuel from plants that died millions of years ago.

数千年前的植物形成了化石燃料。

That life came to earth millions of years ago.

在几百万年前那些生物。

Humans in this galaxy were given a gift millions of years ago by Heaven.

在这个银河系的人类一族早在几百万年以前就被天堂给予了礼物。

What was around the bend in rivers hundreds of millions of years ago?

几亿年前，河湾周围会有些什么呢？

The fossil showed that it began its expansion of territory millions of years ago.

化石显示它从几百万年前就开始了它的领土扩张了。

Millions of years ago, early men used a stick.

几千年以前，早期人类用木棍。

In fact, it is thought that a meteor killed the dinosaurs millions of years ago.

事实上，有人认为在数百万年前就是一块陨石造成所有的恐龙灭绝。

The energy in coal and oil came from the sun, stored there by the plants of millions of years ago.

煤和石油内部的能量来源于太阳，这些煤和石油在数百万年前由植物堆积而成。

Millions of years ago, people lived in caves.

数百万年以前，人们生活在洞。