verb · to become hard or solid, especially as a physical or material process

混凝土需要几天时间才能完全硬化。

verb · to become inflexible or rigid in one's opinions, thinking, or systems

面对飞速发展的时代，我们不能让自己的思想硬化。

verb · the abnormal hardening of body tissue or an organ in a medical context

由于血管硬化，老人的血压一直很不稳定。