质量从来不是偶然的;它始终是智慧努力的结果。
Freedom is not a gift but an achievement that must be won every day.
The most profound theories often arise from the simplest observations.
粮食问题不仅是经济问题,更是政治问题,关系到国家的长治久安。
You have to be comfortable with being uncomfortable if you want to make progress in mathematics.