If it doesn't challenge you, it won't change you.
如果它不挑战你,它就不会改变你。
挑战在于让不可能的事物看起来可信。
The coal industry is the backbone of America.
The biographer's challenge is to be both a detective and a poet.
【译文】 孔子说:“树立崇高理想、培养高尚品德、心怀仁慈友爱、陶冶高雅情操。”