because this is easier to shape than other kinds.

因为燧石较之其他石头更容易成形。

The geologist needs to know what rocks the drill has reached,

地质学家需要知道钻头已经到达什么样的岩层，

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。

a box of pills, or a small jar of ointment,

一盒药丸、一小瓶药膏

And it should not be forgotten how small those resources are in a poor and backward country.

不应忘记，在一个贫穷落后的国家里，那部分财力是很有限的。

however lucky and robust we are.

不管我们多么幸运，多么健壮，