It has been found that certain bats emit squeaks and by receiving the echoes,

人们发现，某些蝙蝠能发出尖叫声，

Precisely at noon an infinitely powerful computer takes all the data and calculates what will happen at each point at 12.01, then 1202, then 12.03.

在正午时分，一个功能巨大的计算机搜集了所有的资料，并算出在每一个点上 12∶01、12∶02、12∶03时可能出现的情况。

Porpoises and sharks are natural enemies.

海豚和鲨鱼是天然仇敌，

He gets the solid shape, as it were, inside his head----

可以这样说，他脑子里得到的是一个立体的概念，

What the child cannot forgive is the parents' refusal to admit these charges if the child knows them to be true.

父母错了，孩子们也看出来了，可是做父母的还不肯承认。

and a very firm hand must be employed in the early stages.

因此开始阶段需要有一位强有力的老手。