抽象的目的不是模糊，而是创建一个新的语义层次，在这个层次上可以绝对精确。
The purpose of abstraction is not to be vague, but to create a new semantic level in which one can be absolutely precise.
有时我们为某些事感到悲伤，却不愿告诉别人。我们想保守这个秘密。或者有时我们感到悲伤，却真的不知道为什么悲伤，于是我们说我们不悲伤，但实际上我们是悲伤的。
To understand the future, one must first understand the past.
The role of business is to produce products and services that make people's lives better—while using fewer resources—and to act lawfully and with integrity.
The Internet is a powerful tool for education, communication, and collaboration.