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Theorems are eternal; their proofs are ephemeral.

The true spirit of delight, the exaltation, the sense of being more than Man, which is the touchstone of the highest excellence, is to be found in mathematics as surely as in poetry.

The soul is healed by being with children.

林業(yè)的未來(lái)在于技術(shù)，但它必須服務(wù)于自然，而不是剝削自然。

Every tree planted today is a legacy for future generations.

世界是由那些出現(xiàn)的人所掌控的。