The most dangerous kind of waste is the waste we do not recognize.
研究历史就是学习时间的语法。
"To be Irish is to know that in the end the world will break your heart."
以公平的价格购买一家优秀的公司远比以优秀的价格购买一家普通的公司要好得多。
The search for reciprocity laws is a fundamental theme in the history of mathematics.