摘要：
黑塞 阅读全文
摘要：
网页记录 阅读全文
摘要：
侧重于应用数学 阅读全文
If you can't explain it simply,
you don't understand it well enough.
Though the night was made for loving,
and the day returns too soon,
yet we'll go no more a-roving
by the light of the moon.