The first step in the art of cutting metals is to find a man who has the necessary skill and experience to do the work.

Words are not mere sounds or marks， but signs of facts.

数学的真正力量在于它能够揭示支配宇宙的隐藏模式和结构。

Your work begins, work that will not be always joyful to you, labor that may not always fulfill you and days that will seem like one damn thing after the other.

没有风险的胜利，就没有荣耀的凯旋。