"Why, you may wonder（想知道）, should spiders be our friends? Because they destroy so many insects, and insects include some of the greatest enemies（敌人） of the human race. Insects would make it impossible for us to live in the world. They would devour（(尤指动物)吞吃） all our crops（农作物） and kill our flocks（羊群） and herds. If it were not for the protection（保护） we get from insect-eating animals. We owe（欠） a lot to the birds and beasts（兽） who eat insects, but all of them put together kill only a fraction（小部分） of the number destroyed by spiders. Moreover（再者）, unlike（不象…） some of the other insect-eaters, spiders never do the least harm（伤害） to us or our belongings.

  Spiders are not insects, as many people think, or even nearly related to them. One can tell the difference almost at a glance（一瞥）, for a spider always has eight legs and an insect never more than six. How many spiders are engaged（使从事于） in this work on our behalf（ 利益）? One authority（当局） on spiders made a census（人口普查） of the spiders in a grass field in the south of England, and he estimated（估计） that there were more than two million two hundred and fifty thousand in one acre（英亩(=607亩)）. That is something like six million spiders of different kinds on a football pitch（程度）. 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（生物）, not content（满意的） 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（全部的） weight of all the human beings in the country.