2-6. Spiders are not insects, as many people think, nor even nearly related to them.
【译文】
蜘蛛不像许多人认为的那样属于昆虫，它们甚至与昆虫毫无关系。
【讲解】
as many people think是插入语，意即“蜘蛛不是像许多人认为的那样是昆虫”。
翻译这一插入语时，必须注意它在句中的位置。不论把它移至句首，译为“正如许多人认为的那样，蜘蛛不是昆虫”，还是将它留在句末，译为“蜘蛛不是昆虫，如同许多人认为的那样”，两种译文都和原意相违。
原句是说“许多人认为蜘蛛是昆虫，而其实不是，他们的看法有误”，而前两种译文的意思则变为“许多人的看法是正确的，他们认为蜘蛛不是昆虫”。
正确的译法应将as many people think置于not（不像）之后、are（属于）之前，译为“蜘蛛不像许多人认为的那样属于昆虫”。这句原文中的…as many people think相当于as many people think spiders are insects。nor even nearly承前省略了are spiders，完整的句子应是：nor are the spiders even nearly related to them。
2-7. One can tell the difference almost at a glance, for a spider always has eight legs and insect never more than six.
【译文】
人们几乎一眼就能看出二者的差异，因为蜘蛛总是8条腿，而昆虫至多有6条腿。
【单词和短语】
at a glance：
2-8. How many spiders are engaged in this work on our behalf?
【译文】有多少蜘蛛正在为我们做这项工作呢？
【单词和短语】
engaged:忙的；从事……的（busy）；
例如：
Engaged in conversation，they did not see me.
他们谈得正来劲，没看见我。
He is engaged on that book.
他正忙于写那部书。
on sb’s behalf:为了某人的利益；为了某人（because of or for someone）。
例如：
Don’t be uneasy on my behalf. 不要为我担心。
该词组的另一含义是“代表某人（instead of someone，or as their representative）”。
例如：
You may sign cheques on our behalf.
你可以代表我们在支票上签字。
2-9. 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.
【译文】
某蜘蛛权威对英国南部某块草坪上的蜘蛛数目统计了一次。他估计每英亩草坪里有超过225万只蜘蛛，即相当于一个足球场上约有6百万只种类各异的蜘蛛。
【单词和短语】
authority：学术权威，专家，泰斗（someone who knows a lot about a subject and whose knowledge and opinions are greatly respected）。某方面的authority需用介词on，
例如：
an authority on preventive medicine 预防医学的权威
something like：接近，大约（close to but not exactly a large amount），
例如：
He is to sell the house for something like $150,000.
他将以大约15万美元的价钱出售这幢房子。
census：统计数量（a process of counting something）。
2-10. Spiders are busy for at least half the year in killing insects.
【译文】
蜘蛛至少有半年在忙于吃虫。
【讲解】
half（形容词）the year是half（名词）of the year的省略形式。
2-11. 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.
【译文】
它们消灭了多少昆虫，我们简直无法猜测，它们是吃不饱的动物，不满足于一日三餐。
【讲解】
it是形式主语，真正的主语是to make more than the wildest guess at how many they kill。It is impossible to…是重点句型，需熟练掌握。not前省略了and they are。
【单词和短语】
content：adj. 满意，满足（happy and satisfied）。
2-12. 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.
【译文】
据估计，在英国一年里被蜘蛛消灭的昆虫的总重量超过该国人口的总重量。
【讲解】
it是形式主语，真正的主语是the weight of all the insects destroyed…in the country。It has been estimated that…是重点句型，需熟练掌握。
