种一棵树最好的时间是二十年前，其次是现在。
The best time to plant a tree was twenty years ago. The second best time is now.
Never stop learning, because the world never stops changing.
Every mental state exists for a purpose; to understand it, we must ask what function it serves in the broader system of behavior.
The future energy structure will be diversified, and the coal industry needs to find its own positioning.