"We sleep safe in our beds because rough men stand ready in the night to visit violence on those who would do us harm."

万一禅关突然打破，美人如玉剑如长虹。

生物学与技术的交汇处正是未来展开的地方。

数学的美只向更有耐心的追随者展示。

The concept of legal validity is crucial for understanding the nature of law.

理论和实践的区别在于，理论上，理论和实践没有区别，但在实践中，却有区别。