释义：只有经过艰苦的努力和考验，才能发现或创造出价值重大的事物。

The Liskov Substitution Principle is a fundamental concept in object-oriented programming, ensuring that derived classes can be used in place of their base classes without altering the correctness of the program.

Sustainability is not a choice anymore—it's our responsibility to future generations.

Not hammer-strokes， but dance of the water sings the pebbles into perfection。