人们说苦难喜欢陪伴，但我认为自由也是如此。

Fearless is not the absence of fear. It’s not being completely unafraid. To me, fearless is having fears. Fearless is having doubts. Lots of them. To me, fearless is living in spite of those things that scare you to death.

The past is always tense, the future perfect.

数学的进步是通过概括实现的。