because this is easier to shape than other kinds.

因为燧石较之其他石头更容易成形。

On the occasions when they have pushed to shore an unconscious human being they have much more likely done it out of curiosity or for sport, as in riding the bow waves of a ship.

当它们偶尔把一个失去知觉的人推到岸边时，更大的可能是出于好奇或游戏，就像它们追逐被船首犁开的浪花一样。

Now the snag in this sort of anecdote is of course that one cannot distinguish cause and effect.

这类奇闻的疑难之处是无法区别因果关系。

and that is what all patients demand of their doctors----to be cured at no inconvenience to themselves.

病要治好，但不要太麻烦。

but the scientific dust has long since settled,

但是，自他逝世以来，那场科学上的纷争早已平息了下来，

Alcohol may be a medical disinfectant, but should not be relied upon to sterilize water.

酒精可能是医学上的消毒剂，但决不可用来消毒饮用水。