小于给定数的素数个数是该数的一个函数。

文学的美在于它让我们活了一千次。

The past is a shadow that follows us, but it is our choice whether to let it define us or to step into the light.

Life seems to go on without effort when I am filled with music. ― George Eliot, The Mill on the Floss

唯一真正的发现之旅不在于寻找新的风景，而在于拥有新的眼光。