【课文】
First listen and then answer the following question.
听录音,然后回答以下问题。
How much of each year do spiders spend killing insects?
Why, you may wonder, should spiders be our friends? Because they destroy so many insects, and insects include some of the greatest enemies of the human race. Insects would make it impossible for us to live in the world; they would devour all our crops and kill our flocks and herds, if it were not for the protection we get from insect-eating animals. We owe a lot to the birds and beasts who eat insects but all of them put together kill only a fraction of the number destroyed by spiders. Moreover, unlike some of the other insect eaters, spiders never do the harm to us or our belongings.
Spiders are not insects, as many people think, nor even nearly related to them. One can tell the difference almost at a glance, for a spider always has eight legs and an insect never more than six.
How many spiders are engaged in this work on our behalf? One authority on spiders made a census of the spiders in grass field in the south of England, and he estimated that there were more than 2,250,000 in one acre; that is something like 6,000,000 spiders of different kinds on a football pitch. Spiders are busy for at least half the year in killing insects. 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. 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.
【New words and expressions 生词和短语】
insect n. 昆虫
devour v. 吞食
flock n. 羊群
herd n. 牧群
beast n. 野兽
fraction n. 小部分
census n. 统计数字
acre n. 英亩
content adj. 满足的
【课文注释】
1. you may wonder 是这个疑问句的插入语。
常见的插入语还有:as you know, to be frank, in fact, generally speaking等等。
2. flock 既可作名词,也可作动词。
①作名词,表示羊群或牛群,或者人群
例句:They kept a small flock of sheep.
他们养了一小群羊。
例句:There are many flocks of tourists in the palace.
宫殿里有好几群游客。
②作动词,表示聚集,群集
例句:In the summer, tourists flock to the museums and art galleries.
夏季游人成群结队到博物馆和艺术馆参观。
③拓展:Birds of a feather flock together.物以类聚,人以群分。
3. if it were not for the protection we get from insect-eating animals,这是一个非真实条件状语从句,were表示虚拟语气。
表示对过去的虚拟:If+过去完成时(had done sth), would/could have done...
表示对现在的虚拟:If+简单过去时(did sth), would/could do...
4. owe a lot to 归功于,感激
①owe money to sb欠某人钱
例句:The company owes money to more than 60 banks.
这家公司欠了60多家银行钱。
②owe sth to sb把某事归功于某人,感谢某人
例句:He owes his success more to luck than to ability.
他认为他的成功是靠运气而不是因为自己有能力.
5. almost at a glance,几乎一眼(就能看出)。
6. on our behalf 代表我们
on behalf of sb/on sb's behalf 代表某人
例句:On behalf of my colleagues and myself I thank you.
我代表我的同事以及我自己向你表示谢意.
【参考译文】
你可能会觉得奇怪, 蜘蛛怎么会是我们的朋友呢?因为它们能消灭那么多的昆虫,其中包括一些人类的大敌,要不是人类受一些食虫动物的保护,昆虫就会使我们无法在地球上生活下去,昆虫会吞食我们的全部庄稼,杀死我们的成群的牛羊。我们要十分感谢那些吃昆虫的鸟和兽,然而把它们所杀死的昆虫全部加在一起也只相当于蜘蛛所消灭的一小部分。此外,蜘蛛不同于其他食虫动物,它们丝毫不危害我们和我们的财物。
许多人认为蜘蛛是昆虫,但它们不是昆虫,甚至与昆虫毫无关系。人们几乎一眼就能看出二者的差异,因为蜘蛛都是8条腿,而昆虫的腿从不超过6条。
有多少蜘蛛在为我们效力呢?一位研究蜘蛛的权威对英国南部一块草坪上的蜘蛛作了一次调查。他估计每英亩草坪里有225万多只蜘蛛。这就是说,在一个足球场上约有600万只不同种类的蜘蛛。蜘蛛至少有半年在忙于吃昆虫。它们一年中消灭了多少昆虫,我们简直无法猜测,它们是吃不饱的动物,不满意一日三餐。据估计,在英国蜘蛛一年里所消灭昆虫的重量超过这个国家人口的总重量。
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