The great secret that all old people share is that you really haven't changed in seventy or eighty years. Your body changes, but you don't change at all.

解释：情绪变化会影响身体生理反应，如贪心时口水增多，悲哀时流泪，体现了情绪与健康的关联。

物理学的美丽在于它能够用最深刻的理论解释最简单的现象。

The harder you work for something, the greater you’ll feel when you achieve it.

幸：追求，希求。斯：这样。干：追求。不追求福运，就不会有灾祸；不计较所得，就不会有失去；不追求荣耀，就不会遭到辱没；不企冀美名，就不会遭到诋毁。