在严冬之中，我发现，在我心中，有一个不可战胜的夏天。
In the midst of winter, I found there was, within me, an invincible summer.
With a library you are free, not confined by temporary political climates. It is the most democratic of institutions because no one - but no one at all - can tell you what to read and when and how.
The mirror is not just a surface, it's a dimension.
2004年9月13日，81岁的杨振宁在清华大学开始为本科生讲授普通物理。他说
理解某事的最好方法就是尝试去改变它。
艺术家必须是无限的影子。