【新概念英语四】第2课 Spare that spider 不要伤害蜘蛛
First listen and then answer the following question.
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
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。
例句：They kept a small flock of sheep.
例句：There are many flocks of tourists in the palace.
例句：In the summer, tourists flock to the museums and art galleries.
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.
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.
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.