The primary rules of obligation are those that require or forbid certain actions.

判断两个λ表达式是否等价的问题是无法解决的。

The greatest question of our time is not communism versus individualism, not Europe versus America, not even the East versus the West; it is whether man can bear to live without God.

We are just an advanced breed of monkeys on a minor planet of a very average star. But we can understand the Universe. That makes us something very special.

生活是愉快的。死亡是平静的。麻烦的是过渡。

The plastic industry must evolve or become obsolete. Sustainability is no longer an option—it's a necessity.