托福听力短文 I-14-2

(woman) Before I tell you about the interesting discovery related to Tyrannosaurus rex, I need to review something we studied last semester --- the difference between what are commonly called cold-blooded and warm-blooded animals. In warm-blooded animals, birds and mammals, for example, the body temperature normally stays within a narrow range, no matter what the outside temperature is. As a result, a warm-blooded animal is usually active in both cold and hot weather because its body temperature can adjust to the temperature of its environment.

On the other hand, cold-blooded animals, such as most reptiles¹, amphibians², and insects, are unable to create enough heat internally to raise their temperature above the temperature of the environment. So, for example, the temperature of a cold-blooded animal falls when the environment is cool.

I hope this distinction is clear. Now, moving on to Tyrannosaurus rex... you may know that dinosaurs³, being reptiles, are generally believed to have been cold-blooded. Well, a recent research study found that the chemical composition of the bones of Tyrannosaurus rex was consistent with the bones of an animal that has a very narrow range of internal temperature, indicating that it was probably warm-blooded.

1 reptiles   

n.爬行动物，爬虫( reptile的名词复数 )

参考例句：

• Snakes and crocodiles are both reptiles. 蛇和鳄鱼都是爬行动物。 来自《简明英汉词典》
• Birds, reptiles and insects come from eggs. 鸟类、爬虫及昆虫是卵生的。 来自《现代汉英综合大词典》

2 amphibians   

两栖动物( amphibian的名词复数 )； 水陆两用车； 水旱两生植物； 水陆两用飞行器

参考例句：

• The skin of amphibians is permeable to water. 两栖动物的皮肤是透水的。
• Two amphibians ferry them out over the sands. 两辆水陆两用车把他们渡过沙滩。

3 dinosaurs   

n.恐龙( dinosaur的名词复数 )；守旧落伍的人，过时落后的东西

参考例句：

• The brontosaurus was one of the largest of all dinosaurs. 雷龙是所有恐龙中最大的一种。 来自《简明英汉词典》
• Dinosaurs have been extinct for millions of years. 恐龙绝种已有几百万年了。 来自《简明英汉词典》