Unit 19 text A

Animals at Risk:Who Cares ?

动物处境危险：谁来关心？

An animal species becomes extinct

当一种动物不能在每一代

when it fails to produce enough young in each generation

都生育出足够的后代以便与死亡率相平衡时，

to keep pace with the death-rate.

它就逐渐灭绝。

We can tell from fossil evidence in rocks

从化石中我们可以找到证据，

that many living species have become extinct over the millions of yearssince life began.

说明自有生命以来在千百万年的时间里，许多生物物种已经成为灭绝。

It is a natural process and extinction is the fate of any animal that has

这是一化，或者其竞争对手更有适应性，

specialized too far to change when its environment changes,

比它更强大，

or has to compete with a better--adapted and more powerful animal.

那么这种动物便命中洽谈室 要灭绝。

Because of remarkable technical developments during the past few centuries,

近几个世纪以来，由于科学技术落后的世大发展，

man has destroyed or nearly destroyed some species

人类以超过动物园繁殖后代的速度来捕杀动物，

by killing them at such a rate that they couldn't produce enough offspring,

或以惊人的速度彻底改变动物的自然环境，

or by completely changing their natural environment at surprising speed.

从而使一些动物物种灭绝或几乎灭绝。

A number of examples can be given of the way

自然环境正在迅速改变的例子可以举出许多，

in which natural environments are being rapidly changed Amazonia,for instance.

亚马逊尼亚国家公园便是一例。

There is every likelihood that many species of animal swill be made extinct

完全有可能，许多种动物由于自然植被在这些

because of these and similar clearances of natural vegetation.

或类似的地方被破坏殆尽而陷于灭绝。

Large numbers of animals have been hunted and killed for food.

大量动物作为肉食而被猎杀。

The North American buffalo is a case of the near-extinction of a species through hunting.

北美洲水牛便是因捕猎而成为濒临灭绝物种的一个例子。

Often the numbers are so great the hunter smay not realize the danger.

动物数量常常很大，捕猎者可能意识不到危险的存在。

But even when the danger is widely publicized,

但即使人们广泛宣传这种危险性

the financial rewards for the hunters

由于经济利益太大，

may be so great that they choose to ignore the threat to the species.

捕猎者会置物种灭绝的危险于不顾。

Attitudes like this have led to hunters killing animals for furs

这种态度已使捕猎者为了取得皮毛、

for ivory or merely for ornaments.

象牙或纯粹为了获得装饰品而猎杀动物；

A slight variation on this is when tourists hunt animals for trophies.

与此稍有不同的是，旅游者猎杀动物是为了获取纪念品。

Magnificent creatures such as lions and tigers

像狮子和老虎之类的大型动物

have been hunted out of existence in some parts of the world.

在世界某些地方已被杀尽。

It is important to realise,

不过，还需要了解的是，

thoughthat animals are sometimes killed out of fear.

有些动物被杀是因为人们害怕它们。

Big cats are killed in this way.

有时某些大型猫科动物就是这样死于非命的。

And animals are sometimes killed out of a wish to reduce numbers

有时人们捕杀动物是为了减少其数量

to help the species to survive.

以使该物种得以生存。

The killing of the Canadian seals is claimed to be for this purpose,

捕杀加拿大海豹据说就是这样的目的，

and the use of their skins for furs is only a by-product.

而利用其皮毛仅是副产品而已。

Many people are concerned about animals and wildlife conservation

许多人关心着对动物和野生生物的保护。

One way to preserve species under threat of extinction

保护濒临灭绝的物种

what ever the cause--is to remove them to zoos and parks and breed them there.

不管何种原因造成的——其办法之一是将这些物种迁移到动物园和公园里饲养

There is always the chance that enough offspring will be born

总是有可能将其后代繁殖到足够数量

to return them one day to their natural environment--provided it still exists,

以便有朝一日放回到自然环境中去——如果这种物种还存在

and that hunters don't kill them again!

而且人类不再捕杀它的话！

Another method is to protect the animals in their natural environment

另一种办法是建立野生动物禁猎区或野生动物园并且雇用禁猎人员看守

by creating wildlife reserves and parks and using game wardens to look after them.

以此保护动物生活在自然的环境里。

But the parks are large,

但是野生动物园范围大，

the wardens few and the determination of hunters very great.

看护人员少，而捕猎者又敢于挺而走险。

Early in 1980 wardens and hunters clashed in East Africa.

1980年初看护人与捕猎人在东非发生冲突，捕猎者配备现代化武器，死了好几个人。

The hunters were armed with modem weapons and several people were killed.

在自然的或接近自然的环境里观看野生动物会是一种很大的乐趣。

There is great pleasure in watching wildlife in natural or nearnatural environments

and tourism can add to the income of countries.

这样的旅游业能给国家增加收入

The animals are still resources--but in a very different form.

动物仍是资源——只是另一种形式上十分不同的资源罢了。

Text B

The Killer Smogs

致命烟雾

On the night of December 1,1930,

1930年12月1日晚，

a dense fog moved over the Meuse Valley, in Belgium.

一片浓雾笼罩着比利时默兹河流域，

Many factories in the valley poured smoke and fumes into the foggy air.

那里的许多工厂将大量烟尘排入雾气蒙蒙的空中，

This created a dark smog of smoke and fog combined.

这样形成了烟与雾的混合物：黑色的烟雾。

People in the valley began to cough and strain for breath.

那个地区的居民开始咳嗽，呼吸困难。

The smog remained for four days.

烟雾持续了四天

During that time, thousands of people became ill.

在此期间，有几千人得病。

The hospitals were filled with patients.

医院里住满了病人，

Sixty people died.

有60人死亡，

Most of them were older persons with heart and lung problems.

多数为患有心肺疾病的老年人。

Finally, a heavy rain washed away the smog.

最后一场大雨将烟雾冲洗掉。

Scientists studied the courses of the disaster.

科学研究了疾病的原因，

They concluded that the illnesses and deaths

得出的结论是疾病和死亡都是烟雾中的

were coursed by chemicals in the smog.

化学物质所致。

The first reported event of this kind in the United Stateshappened in Donora,

美国首次报告的这类事件发生在多诺拉，

a factory town in a valley near Pittsburgh.

这是靠近匹兹堡的一个工业小镇

In 1948, a killer smog made half of the population sickthere were 17 deaths.

1948年致人死命的烟雾使一半居民得病，17人死亡。

Again, older people with lung or heart diseases were hit hardest.

同样，患有肺病或心脏病的老年人受害最甚。

London,England, has always been known for its "black fogs."

英国伦敦一向以“黑雾”而闻名。

In the winter of 1952, a milky white fog rolled into the city.

1952年冬天，一股乳白色的大雾滚滚涌入这个城市。

It soon turned into black smog as the smoke of the citypoured into the air.

随着城市的烟尘排入天空，白雾很快变成黑色烟雾。

It was so hard to see

看东西很困难，

that people had to walkin front of the buses to guide them.

人们不得不走在公共汽车前面为汽车引路。

In this way, the most serious air pollution disaster in history began.

就这样开创了历史上最严重的空气污染的灾难。

When it was over, more than 4,0130 peoplehad been killed by the thick black smog.

当这场灾难结束时，有4000多人死于浓黑的烟雾。

New York City has had several London-type smogs since 1950.

自1950年以来，纽约市发生过几次伦敦式的烟雾。

Each time, there were from 100 to 400 deaths caused by the smog.

每次烟雾都造成100至400人死亡。

Although these smogs were not as deadly as London's,

虽然这些烟雾不像伦敦烟雾那么可怕，

New York City has the worst air pollution problem in the United States.

但纽约市的空气污染问题在美国是最严重的

In all the killer smogs,

在各种致人死命的烟雾中，

factories and homes poured smokeand fumes into the air from the furnaces.

有工厂和家庭炉灶里排放到空气中的烟尘。

The chemical fumes combined with the water droplets in the fog

化学烟尘与雾气中的水珠结合

to form harmful substances.

在一起形成有害物质。

These substances caused the illness of those who breathed the polluted air.

这些物质便使吸入这种污染空气的人得病。

Usually,such harmful fumes rise into the upper airand are blown away by the wind.

这种有害烟尘通常会上升到空气的上层，被风吹散。

But sometimes there is an unusual weather condition

但有时有一种特殊的天气状况

called a temperature inversion.

称为温度逆增。

A layer of cold air remains near the ground as smoke and fumes pour into it

当烟尘排入空气时，冷空气层依然靠近地面，

This is covered by an upper layer of warm air that acts like a lid.

而在外层是暖空气，就像一个盖子。

It prevents the polluted cooler air from rising.

外层暖空气阻碍污染的冷空气上升。

The harmful fumes pile up and make people ill.

这样，有害烟尘便聚集起来，使人得病。

The smog may be so thick that airprts are closed

烟雾有可能很浓，使得机场被迫关闭，

and chains of collisions occur on the highways.

公路上会发生连续的撞车事故。

Another type of smog occurs in Los Angeles.

还有一类烟雾出现在洛杉矶。

Here the weather may be clear and sunny.

那里天气晴朗，阳光灿烂。

But stinging eyes and dry coughs show that harmful chemicals fill the air

但是人们干咳，眼睛刺痛，说明空气里充满有害化学物质。

The smog is due to invisible gases, mostly from automobile exhaust.

这种烟雾是由一些看不见的气体，其中大部分是汽车废气造成的。

Because these chemicals are changed by the sun high up in the air,

因为这些化学物质被高空中的阳光照射而发生变化，

Los Angeles smog is called photochemical smog.

所以洛杉矶烟雾叫做光化烟雾。

It contains automobile exhaust fumes

这种烟雾含有汽车排出的废气

and nitrogen oxides changed by the sun's rays.

和被阳光照射后发生变化的氧化氮。

Added to these are sulfur dioxide

除此之外，还有从工厂

and other fumesfrom factories and oil refineries.

与炼油厂排放出来的二氧化硫和其他烟尘。

Photochemical smog is found in many large cities all over the world.

全世界许多大城市都有光化烟雾。

Killer smogs don't happen very often,fortunately.

幸亏致人死命的烟雾不常出现。

But in many large cities,

但在许多城市，汽车废气、

a combination of automobile exhaust fumeshome furnace smoke,

家用炉灶冒出的烟尘以

and factory waste gases pours into the air.

及工厂废气都排放到空气中。

This may also happen in the suburbs,or out in the country,

这种情况也还可能出现在建有大型工厂的

where large factories have been built.

郊区与离城市的农村。

A number of harmful substances have been found in the air there.

在这种气体中存在一些有害物质。

When these substances are breathed in day after day,

人们日复一日地吸入这些有害物质，

the health of the population is affected.

身体健康受到了影响。