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外交是一門沒有永久朋友，只有永久利益的學科。

我相信詩歌是一種表達無法表達之物的方式。

I don't have any particular recipe [for developing new proofs] ... It is the reason why doing research is challenging as well as attractive. It's like being lost in a jungle and trying to use all the knowledge that you can gather to come up with some new tricks, and with some luck you might find a way out.

如果你害怕失敗，那你很有可能會失敗。