The human being needs sadness as much as he needs joy.
人类需要悲伤，正如需要欢乐一样。
You can’t change the past, but you can shape the future.
The power of economics lies in its ability to reveal hidden truths about how the world works.
水产养殖的未来在于平衡生态健康与经济可行性。
Understanding the computational complexity of learning problems is essential for developing efficient algorithms.