历史上的动物可真巨大！比如，曾经生活在亚洲地区的巨犀 “Paraceratherium” 比两辆双层公交车叠在一起还要高；体型庞大的巨齿鲨 “megalodon” 和阿根廷巨鹰 “Argentavis” 也分别曾在海洋和天空中遨游。本文介绍除了恐龙之外地球上还曾出现过哪些巨大生物，并浅谈这些生物出现的原因。

词汇：animal 动物

1 When thinking of giant animals, dinosaurs might be the first creatures you think of. But before the dinosaurs became extinct, and before the first ever humans existed, there was megafauna. In zoology, this means large animals.

2 One of the largest known mammals to have ever walked the Earth is the Paraceratherium – picture a gigantic hornless rhino, and you'll have a rough idea of what they looked like. They lived around 25 million years ago and were most common in areas of the world that are now part of Asia, such as China, India and Kazakhstan. From excavated fossils, these creatures are estimated to have been almost six metres tall – that's the height of two buses on top of each other!

3 And it's not just land enormous creatures lived on – they were in the skies and oceans too. The Argentavis is the largest flying bird to have been discovered. It lived until around six million years ago and had a wingspan of seven metres, over twice the size of the Andean condor, which is one of the largest birds on Earth today. And we can't forget the giant shark that roamed the oceans, megalodon. Imagine swimming in the sea and coming across an 18-metre-long shark! Don't worry. They died out around 2.6 million years ago.

4 So, why were pre-historic animals so huge? There are a number of reasons. One is that, in the past, resources were more plentiful, so species were able to grow larger because they could eat more. Scientists also believe that during certain periods of history, such as in the Carboniferous period, there were higher oxygen levels on Earth. At this time, some insects grew to the size of cars because of better oxygen delivery in their tracheal system, the network of tubes that enable insects to breathe.

5 Can you picture animals being so huge today?

测验与练习

一、根据文章内容选出正确的段落。

1. Which paragraph mentioned huge insects?

二、根据文章内容选出正确的选项。

1. The largest animal ever was a hornless rhino.
a. True
b. False
c. Not given

2. How tall was the Paraceratherium?
a. under six metres
b. six metres
c. over six metres

3. How large was the giant bird, Argentavis?
a. larger than a megalodon
b. around double the length of the Andean condor
c. smaller than some birds today

4. Megalodons roamed the ocean 2.5 million years ago.
a. True
b. False
c. Not given

5. What does 'this' refer to in the following sentence? At this time, some insects grew to the size of cars because of better oxygen delivery in their trachea.
a. the Carboniferous period
b. certain periods of history
c. modern day

三、用下列单词完成对本文的总结。

Looking at 1)_______, scientists have found a range of creatures that used to be 2)_______. For example, the Paraceratherium was a 3)_______ not too dissimilar to a rhino. The 4)_______ bird ever found, with a 5)_______ of 7 metres was almost twice the size of the Andean condor. These animals were so huge for a range of reasons, including there being more resources, like food, than today.

largest
megalodon
enormous
fossils
wingspan
mammal
died out

（答案见词汇表后） 

词汇表

giant 巨大的，高大的
dinosaur 恐龙
extinct 灭绝的
megafauna 巨型动物
zoology 动物学
mammal 哺乳动物
gigantic 巨大的，庞大的
hornless 没有角的
excavate 发掘，挖掘
fossil 化石
land 陆地
wingspan 翼展，一对翅膀展开后的总宽度
condor 秃鹰
roam 漫步，漫游
megalodon 巨齿鲨
die out 逐渐消失
pre-historic 史前的
plentiful 充足的，富足的
Carboniferous 石炭纪
tracheal system （昆虫的）气管系统

答案

一、根据文章内容选出正确的段落。

Paragraph 4. Scientists also believe that during certain periods of history, such as the Carboniferous period, there were higher oxygen levels on earth. At this time, some insects grew to the size of cars.

二 、根据文章内容选出正确的选项。

1. c. Not given. One of the largest knownmammals to have ever walked the earth is the Paraceratherium, a gigantic hornless rhino.

2. a. These creatures are estimated to have been almost six metres tall.

3. b. The Argentavis had a wingspan of seven metres, over twice the size of the Andean condor, which is one of the largest birds on earth today.

4. b. False. They died out around 2.6 million years ago.

5. a. The pronoun 'this' refers back to the sentence 'Scientists also believe that during certain periods of history, such as the Carboniferous period, there were higher oxygen levels on earth.'

三、用下列单词完成对本文的总结。

Looking at fossils, scientists have found a range of creatures that used to be enormous. For example, the Paraceratherium was a mammal not too dissimilar to a rhino. The largest bird ever found, with a wingspan of seven metres, was almost twice the size of the Andean condor. These animals were so huge for a range of reasons, including there being more resources, like food, than today.