免费的疫苗比昂贵的治疗更有价值，但更难推广。

It is indeed an opinion strangely prevailing amongst men， that houses， mountains， rivers， and in a word all sensible objects， have an existence， natural or real， distinct from their being perceived by the understanding.

解释：处于安全环境时要考虑到可能出现的危险，考虑到危险就会有所准备，事先有了准备就可以避免祸患。

Paperless offices still need paper-producing forests.

The state of nature has a law of nature to govern it, which obliges every one: and reason, which is that law, teaches all mankind, who will but consult it, that being all equal and independent, no one ought to harm another in his life, health, liberty, or possessions.

"A child who reads will never be bored."