Coal companies must fulfill their social responsibilities while pursuing economic benefits.

太阳在天空中闪耀，眼前没有一片云彩。

心灵是一个不断进化的过程。

Understanding the computational complexity of learning problems is essential for developing efficient algorithms.

人生は、自分で選んだ道を歩くことだ。

一个人的记忆里可能只有一百个清晰的日子，而他已经活过了数千天。