Lesson 02 Spare That Spider
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 least harm to us or our belongings.
Spiders are not insects, as many people think, not 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 a 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 of 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.
文章讲解
📋 文章主题
这是一篇说明文，主题是：蜘蛛是人类的朋友，因为它们大量捕食昆虫。
🎯 文章结构分析
第一段：蜘蛛的重要作用
- 核心观点：蜘蛛通过消灭昆虫保护人类
- 论证逻辑：
- 昆虫是人类的大敌（会毁坏庄稼、杀死牲畜）
- 食虫动物保护了我们
- 蜘蛛杀死的昆虫数量远超其他食虫动物
- 蜘蛛对人类无害
第二段：蜘蛛与昆虫的区别
- 纠正常见误解：蜘蛛不是昆虫
- 简单辨别方法：蜘蛛8条腿，昆虫最多6条腿
第三段：惊人的数据
用具体数字说明蜘蛛的贡献：
- 密度：英格兰南部草地，每英亩超过225万只蜘蛛
- 换算：一个足球场大小约有600万只不同种类的蜘蛛
- 工作时长：每年至少半年在捕食昆虫
- 食量：英国蜘蛛一年消灭的昆虫总重量 > 全国人口总重量
📚 重点词汇解析
| 单词 | 词性 | 含义 | 用法 |
|---|---|---|---|
| devour | v. | 吞食，毁灭 | devour all our crops |
| flocks | n. | 羊群 | flocks and herds（成对使用） |
| herds | n. | 牛群 | 指大型牲畜群 |
| beasts | n. | 野兽，动物 | birds and beasts（鸟兽） |
| glance | n. | 一瞥 | at a glance（一眼就能看出） |
| behalf | n. | 利益，代表 | on our behalf（为我们） |
| census | n. | 普查，统计 | make a census of… |
| acre | n. | 英亩 | 面积单位（约4047平方米） |
| pitch | n. | 球场 | football pitch（足球场） |
✨ 精彩表达
“insects include some of the greatest enemies of the human race”
- 昆虫是人类最大的敌人之一
“all of them put together kill only a fraction of…”
- 所有这些加起来也只杀死了一小部分
- put together = 加在一起
“never do the least harm to us”
- 从不对我们造成丝毫伤害
- not the least = 一点也不
“not content with only three meals a day”
- 不满足于一日三餐
- 形容蜘蛛食量大
🔢 回答标题问题
“How much of each year do spiders spend killing insects?”
答案：文中明确指出 “at least half the year”（至少半年）
💡 写作手法
- 设问开篇：引发读者思考
- 数据支撑：用具体统计增强说服力
- 对比论证：蜘蛛 vs 其他食虫动物
- 纠正误解：科普蜘蛛不是昆虫
- 夸张修辞：昆虫重量 > 人口重量（强调效果）
这是一篇典型的科普说明文，逻辑清晰，数据详实，语言生动！