数学中的希腊字母
posted on 2020-04-22 21:24 DataMaySpeak 阅读(29) 评论(0) 收藏 举报
DataMaySpeak
Yesterday is a history ; tomorrow is a mystery ; today is a gift . That's why we call it present .
Yesterday is a history ; tomorrow is a mystery ; today is a gift . That's why we call it present .
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