The thing about happiness is that you only know you had it when it's gone.

There is no love that’s so right as admiration-based love, and that love should include the instructive dead. Somehow, I got that idea and I lived with it all my life and it’s been very very useful to me.

The increase of national wealth depends chiefly upon the increase of production.

学习就像种树，春天赏花，秋天收获果实；讨论文章如同春天的花，修养身心、付诸实践才是秋天的果实。

Anyone who recovers from an addiction has my respect.

物理学的美丽在于它能够用一些基本原理来描述宇宙。