Lesson 2 Spare that spider不要傷害蜘蛛

First listen and then answer the following question.
聽(tīng)錄音，然后回答以下問(wèn)題。
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.
你可能會(huì)覺(jué)得奇怪， 蜘蛛怎么會(huì)是我們的朋友呢？因?yàn)樗鼈兡芟麥缒敲炊嗟睦ハx(chóng)，其中包括一些人類(lèi)的大敵，要不是人類(lèi)受一些食蟲(chóng)動(dòng)物的保護(hù)，昆蟲(chóng)就會(huì)使我們無(wú)法在地球上生活下 去，昆蟲(chóng)會(huì)吞食我們的全部莊稼，殺死我們的成群的牛羊。我們要十分感謝那些吃昆蟲(chóng)的鳥(niǎo)和獸，然而把它們所殺死的昆蟲(chóng)全部加在一起也只相當(dāng)于蜘蛛所消滅的一 小部分。此外，蜘蛛不同于其他食蟲(chóng)動(dòng)物，它們絲毫不危害我們和我們的財(cái)物。

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 insect never more than six
許多人認(rèn)為蜘蛛是昆蟲(chóng)，但它們不是昆蟲(chóng)，甚至與昆蟲(chóng)毫無(wú)關(guān)系。人們幾乎一眼就能看出二者的差異，因?yàn)橹┲攵际?條腿，而昆蟲(chóng)的腿從不超過(guò)6條。
.
How many spiders are engaged in this work no 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.
有多少蜘蛛在為我們效力呢？一位研究蜘蛛的權(quán)威對(duì)英國(guó)南部一塊草坪上的蜘蛛作了一次調(diào)查。他估計(jì)每英畝草坪里有225萬(wàn)多只蜘蛛。這就是說(shuō)，在一個(gè)足球場(chǎng) 上約有600萬(wàn)只不同種類(lèi)的蜘蛛。蜘蛛至少有半年在忙于吃昆蟲(chóng)。它們一年中消滅了多少昆蟲(chóng)，我們簡(jiǎn)直無(wú)法猜測(cè)，它們是吃不飽的動(dòng)物，不滿意一日三餐。據(jù)估 計(jì)，在英國(guó)蜘蛛一年里所消滅昆蟲(chóng)的重量超過(guò)這個(gè)國(guó)家人口的總重量。

New words and expressions 生詞和短語(yǔ)
insect
n. 昆蟲(chóng)

devour
v. 吞食

flock
n. 羊群

herd
n. 牧群

beast
n. 野獸

fraction
n. 小部分

census
n. 統(tǒng)計(jì)數(shù)字

acre
n. 英畝

content
adj. 滿足的

Notes on the text課文注釋
1 you may wonder 是這個(gè)疑問(wèn)句的插入語(yǔ)。
2 if it were not for the protection we get from insect-eatting animals，這是個(gè)非真實(shí)條件狀語(yǔ)從句.were表示虛擬語(yǔ)氣。
3 almost at a glance，幾乎一眼(就能看出)。

Lesson 2 課后練習(xí)和答案Exercises and Answer