The time of life is limited and unchangeable, so it is necessary to use every minute efficiently. Not using it well is a waste.

Never give up, never surrender.

化合价的概念是理解化学键的关键。

探索未知是人类永恒的追求。

释义：如果两人志趣相投，即使隔着高山和大海也不会感到遥远，如果两人理念不合，近在眼前也觉得心离得远。