历史学家是反向的先知。
The historian is a prophet in reverse.
人は、失敗から学ぶものだ。
经济学特别是宏观经济学中说的投资是耐用资本品如厂房设备的生产，而平常说的“投资”是指购买资产如股票，这和经济学中的投资不同，为了区分，这种投资被称为金融投资。
So given a Time Turner, I would tell my 21-year-old self that personal happiness lies in knowing that life is not a check-list of acquisition or achievement. Your qualifications, your CV, are not your life, though you will meet many people of my age and older who confuse the two. Life is difficult, and complicated, and beyond anyone’s total control, and the humility to know that will enable you to survive its vicissitudes.
The most dangerous thing in the digital era is not making mistakes, but missing opportunities.
The truth is not always what it seems, and sometimes it is better not to know it.