地球上的哺乳动物起源于何时？

When did mammals appear on the earth?

《牛津词典》

海洋哺乳动物一般顺水而游。

Marine mammals generally swim with the current.

《牛津词典》

只有约百分之五的哺乳动物是单一配偶的。

Only about five percent of mammals are monogamous.

《柯林斯英汉双解大词典》

食肉动物通常是有着复杂的社会关系的哺乳动物。

Carnivores are usually socially complex mammals.

《牛津词典》

有人提出哺乳动物是在6 500万年前取代恐龙的。

It has been suggested that mammals took over from dinosaurs 65 million years ago.

《牛津词典》

人类经历着一个迟来的成熟；我们进入生命各个阶段的时间比其他哺乳动物要晚。

Humans experience a delayed maturity; we arrive at all stages of life later than other mammals.

《柯林斯英汉双解大词典》

大约35%的哺乳动物物种消失了。

About 35 percent of mammal species were lost.

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恐龙、昆虫和哺乳动物飞上了天空。

Dinosaurs, insects and mammals took to the air.

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很多哺乳动物已经到达这一点。

Most mammals have reached this point.

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哺乳动物是从母体中分娩出来的。

Mammals are born alive from their mothers.

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大多数哺乳动物生活在陆地上。

Most mammals live on land.

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鲸是生活在海洋中的哺乳动物。

Whales are mammals that live in the sea.

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大多数哺乳动物用脚趾走路。

Most mammals walk on their toes.

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蝙蝠是唯一能飞的哺乳动物。

Bats is the only mammal that can fly.

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蟒主要吃鸟和小的哺乳动物。

Pythons mainly feed on birds and small mammals.

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哺乳动物是什么时候出现在地球上的？

When did the mammals appear at the earth?

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它是最不受保护的哺乳动物。

It is the least protected mammal species.

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猫、狗和猴子都是哺乳动物。

Cats, dogs, and monkeys are some mammals.

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猴子和狗都是哺乳动物。

Monkeys and dogs are mammals.

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松鼠是哺乳动物，对吗？

Squirrels are mammals, right?

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我对哺乳动物很感兴趣。

I am very interested in mammals.

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我们今天在课堂上学了有关哺乳动物的知识。

We learned about mammals in class today.

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骆驼是一种哺乳动物，但是几维鸟是一种鸟。

The camel is a mammal, but the kiwi is a bird.

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鲸是一种哺乳动物。

A whale is a kind of mammal.

《新英汉大辞典》

相比于爬行动物，哺乳动物的这一特性更加典型。

This is more typical of mammals than of reptiles.

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并不是所有的大型哺乳动物都在那个时期灭绝了。

Not all large mammals died out at that time.

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鲸鱼是哺乳动物。

The whale is a mammal.

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对于小型哺乳动物来说，微气候可以产生很大的影响。

For small mammals, microclimates can make a big difference.

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我们知道像狗这样的哺乳动物会发出很多不同的声音。

We know that mammals, dogs for example, dogs vocalize many different sounds.

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与许多哺乳动物不同的是，它们不会做出类似人类的行为。

Unlike many mammals they do not engage in human-like behaviour.

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