La palabra es el instrumento más poderoso que tenemos para cambiar el mundo.

You take delight not in a city’s seven or seventy wonders, but in the answer it gives to a question of yours.

I sent my Soul through the Invisible, Some letter of that After-life to spell: And by and by my Soul return'd to me, And answer'd "I Myself am Heav'n and Hell."

化合价的概念是理解化学键的关键。

"The dawn right before the sun rises is the darkest."

译文：与其在生病后去求取药物，不如在生病前做好自我的预防。赏析：任何事都要提前谋划，防患未然，事到临头才不会手忙脚乱。平时不烧香，临时抱佛脚是没有用的。