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。

When anyone opens a current account at a bank,

任何人在银行开一个活期账户，

and these will ply the short wings with such irresistible power that they can bore for long distances through an opposing gale before exhaustion follows.

这些肌肉以巨大的力量扇动短小的翅膀，使这类鸟能顶着大风飞行很远的路才会疲劳。

History does not relate whether his friend accepted his medical help, but in all probability he did.

他的朋友是否接受了他的药物治疗，历史没有记载，但很可能是接受了。

The Moon is likely to become the industrial hub of the Solar System,

月球很可能成为太阳系的工业中心。

and are capable of a considerable degree of personal affection.

而且会对主人产生相当深厚的私人感情。