I sent my Soul through the Invisible, Some letter of that After-life to spell: And by and by my Soul return'd to me, And answer'd "I Myself am Heav'n and Hell."

数学的美只向更有耐心的追随者展示。

永远不要停止学习，因为世界永远不会停止变化。

I always tell my students that it's okay to make mistakes, as long as you learn from them.

The urban artifact is a work of art and a historical document.

书是一次心灵的旅程。