过去是幽灵，未来是梦，我们拥有的只有现在。
The past is a ghost, the future a dream, and all we ever have is now.
"A good story should make you laugh and cry in equal measure."
The test of a first-rate intelligence is the ability to hold two opposed ideas in mind at the same time and still retain the ability to function.
平静：不要被琐事、普通或者不可避免的事所扰。
发现的喜悦是推动数学家前进的动力。