种树的最佳时间是二十年前，其次是现在。

物理学家是一位探险家，他不满足于停留在已知世界的边界内。

The holographic principle suggests that the information in a volume of space can be thought of as encoded on a boundary to that space.

"Books are the quietest and most constant of friends; they are the most accessible and wisest of counselors, and the most patient of teachers."

今天对自由民主最严重的威胁不是来自外部，而是来自内部。