Sustainability isn't a choice—it's a responsibility we owe to the next generation.
可持续性不是一种选择，而是我们对下一代的责任。
——晚年访谈
Silence is not always absence; sometimes it is the loudest presence.
教育的首要目标是培养能够做新事情的人，而不仅仅是重复前几代人所做的事情。
水是一切事物的根源。
Success is not final, failure is not fatal: it is the courage to continue that counts.
An understanding of the natural world and what's in it is a source of not only a great curiosity but great fulfillment.
If you pick up a starving dog and make him prosperous, he will not bite you. This is the principal difference between a dog and a man.