第2课

旁白 neutral

Because they destroy so many insects, and insects include some of the greatest enemies of the human race.

因为它们消灭了那么多昆虫，而昆虫中有些是人类最大的敌人。

旁白 neutral

Insects would make it impossible for us to live in the world;

昆虫会使我们无法在这个世界上生存；

旁白 neutral

they would devour all our crops and kill our flocks and herds,

它们会吞噬我们所有的庄稼，杀死我们的家禽和牲畜，

旁白 neutral

if it were not for the protection we get from insect eating animals.

如果不是因为食虫动物为我们提供保护的话。

旁白 neutral

We owe a lot to the birds and beasts who eat insects

我们对那些吃昆虫的鸟兽负有很多，

旁白 neutral

but all of them put together kill only a fraction of the number destroyed by spiders.

但它们合在一起消灭的昆虫数量，只是蜘蛛消灭数量的一小部分。

旁白 neutral

Moreover, unlike some of the other insect eaters, spiders never do the least harm to us or our belongings.

此外，不像其他一些食虫动物，蜘蛛从不对我们或我们的财物造成丝毫损害。

旁白 neutral

Spiders are not insects, as many people think, nor even nearly related to them.

蜘蛛不是昆虫，正如许多人认为的那样，甚至与昆虫没有多少亲缘关系。

旁白 neutral

One can tell the difference almost at a glance, for a spider always has eight legs and an insect never more than six.

几乎一眼就能看出区别，因为蜘蛛总是有八条腿，而昆虫从不超过六条。

旁白 neutral

How many spiders are engaged in this work on our behalf?

有多少蜘蛛正在为我们做这项工作呢？

旁白 neutral

One authority on spiders made a census of the spiders in a grass field in the south of England,

一位研究蜘蛛的权威人士在英格兰南部的一片草地上对蜘蛛进行了普查，

旁白 neutral

and he estimated that there were more than 2,250,000 in one acre;

他估计每英亩有225万多只蜘蛛；

旁白 neutral

that is something like 6,000,000 spiders of different kinds on a football pitch.

这相当于一个足球场上有大约600万只不同种类的蜘蛛。

旁白 neutral

Spiders are busy for at least half the year in killing insects.

蜘蛛每年至少有半年时间忙于捕杀昆虫。

旁白 neutral

It is impossible to make more than the wildest guess at how many they kill, but they are hungry creatures, not content with only three meals a day.

要精确估计它们捕杀了多少昆虫是不可能的，只能进行最大胆的猜测，但它们是饥饿的生物，不满足于一天三餐。

旁白 neutral

It has been estimated that the weight of all the insects destroyed by spiders in Britain in one year would be greater than the total weight of all the human beings in the country.

据估计，在英国一年内被蜘蛛消灭的所有昆虫的重量，将超过该国所有人类的总重量。