1. 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.
我们要十分感谢那些吃昆虫的鸟和兽，然而把它们所杀死的昆虫全部加在一起也只相当于蜘蛛所消灭的一小部分。
owe to 归功于
例句：He owes his success more to luck than to ability.
他认为他的成功是靠运气而不是因为自己有能力。
2. Moreover，unlike some of the other insect eaters，spiders never do the harm to us or our belongings.
此外，蜘蛛不同于其他食虫动物，它们丝毫不危害我们和我们的财物。
Moreover递进，相当于what's more
do harm to 损害……，伤害……
例句：Whether it will do us harm or good is hard to say.
这对我们是好是坏还很难说。
3. One can tell the difference almost at a glance，for a spider always has eight legs and insect never more than six.
人们几乎一眼就能看出二者的差异，因为蜘蛛都是8条腿，而昆虫的腿从不超过6条。
at a glance 一眼看去,一瞥,扫一眼
例句：He saw at a glance that she'd been crying.
他一看便知她一直在哭。
4. 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.
它们一年中消灭了多少昆虫，我们简直无法猜测，它们是吃不饱的动物，不满意一日三餐。
content with 满足于……
例句：I will never be content with my performance in the market.
我不满足于现有的成就。
