The past is always with us, for it feeds the present.

The general will is always right， but the judgment which guides it is not always enlightened.

年轻时，你以为长大后就会幸福。但长大后，你意识到年轻时的自己才是幸福的。

"Time is the school in which we learn, time is the fire in which we burn."

Nature has been the greatest chemist of all time, and we are just beginning to understand its secrets.

解析：告诫人们要珍惜所得。

I want my books to be a mirror, not a window.

"A novel is a mirror carried along a high road. Sometimes it reflects to your eyes the blue of the skies, at others the churned-up mud of the road."