[ar:MP3 同步字幕版(美音)]
[ti:Spare That Spider]
[by:更多学习内容,请到
yingyu.chazidian.com
搜索“新概念”]
[00:00.39]Lesson 2
[00:08.72]How much of each year do spiders spend killing insects?
[00:14.83]Why, you may wonder, should spiders be our friends?
[00:19.15]Because they destroy so many insects, and insects include some of the greatest enemies of the human race.
[00:26.74]Insects would make it impossible for us to live in the world;
[00:30.38]they would devour all our crops and kill our flocks and herds,
[00:34.62]if it were not for the protection we get from insect eating animals.
[00:39.77]We owe a lot to the birds and beasts who eat insects
[00:43.73]but all of them put together kill only a fraction of the number destroyed by spiders.
[00:49.79]Moreover, unlike some of the other insect eaters, spiders never do the least harm to us or our belongings.
[00:58.72]Spiders are not insects, as many people think, nor even nearly related to them.
[01:05.22]One can tell the difference almost at a glance, for a spider always has eight legs and an insect never more than six.
[01:14.93]How many spiders are engaged in this work on our behalf?
[01:19.25]One authority on spiders made a census of the spiders in a grass field in the south of England,
[01:25.79]and he estimated that there were more than 2, 250, 000 in one acre;
[01:33.18]that is something like 6, 000, 000 spiders of different kinds on a football pitch.