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A mathematician's work is never truly finished; there is always more to explore.

對(duì)于任何事務(wù)，要改變它就要先接受它。譴責(zé)不會(huì)解放而只會(huì)壓迫。

"A book is a friend that never lets you down."

教育兒童，就不需要懲罰成年人。