我们都只是曾经存在的某种东西的回声。
We are all just echoes of something that once was.
Only our individual faith in freedom can keep us free.
Quality is never an accident; it's the result of intelligent effort and relentless focus.
Nothing can stop the man with the right mental attitude from achieving his goal; nothing on earth can help the man with the wrong mental attitude.
The true challenge in mathematics is not solving problems, but asking the right questions.