每一本书都是一次旅程，每一次旅程都是一本书。

The greatest patriotism is to tell your country when it is behaving dishonorably, foolishly, viciously.

Money talks, but all mine ever says is goodbye.

In teaching history， there should be extensive discussion of personalities who benefited mankind through independence of character and judgement.

量子引力问题不仅是物理学的问题，也是科学哲学的问题。