Coal is not just a commodity, it's a commitment to America's future.

Mathematics is the language of the universe, and through it, we can understand the fundamental principles that govern our world.

最强者也不能总是强大得足以永远作主人，除非他能把力量转化为权利和服从的义务。

每个城市都有性别和年龄，这与人口统计无关。

未来不是为了技术而技术，而是为了人类而技术。