Because they destroy so many insects, and insects include some of the greatest enemies of the human race.

因为它们能消灭那么多的昆虫，其中包括一些人类的大敌，

Marine Studio biologists have pointed out that, however intelligent they may be, it is probably a mistake to credit dolphins with any motive of lifesaving.

海洋摄影室的生物学家指出，无论海豚多么聪明，认为它们有救人的动机可能是错误的。

With the invention of writing, a great advance was made, for knowledge could then be not only communicated but also stored.

随着书写的发明，又迈进了一大步，因为这样一来，知识不仅能交流，而且能储存了。

He must, for example, perceive an egg as a simple single solid shape,

以鸟蛋为例，观赏者必须感觉到它是一个单一的实体形态，

punctuated by textbooks----those purchasable wells of wisdom----

并以教科书-那些可以买到的智慧源泉-予以强化，

he might as well try to explain a crime or a love affair.

他还不如给人讲一个犯罪案件或一个恋爱故事。