"Randomized experiments are the gold standard for causal inference, but they are not always feasible."
随机实验是因果推理的黄金标准，但它们并不总是可行的。
恨也罢，爱也罢，思想、感觉、观察也罢，无非都是在领悟。
新的大国的崛起总是引起现有大国的担忧，因为它威胁到现有的权力平衡。
世事犹如书籍，一页页被翻过去。人要向前看，少翻历史旧账。
"Stories you read when you're the right age never quite leave you. You may forget who wrote them or what the story was called. Sometimes you'll forget precisely what happened, but if a story touches you it will stay with you, haunting the places in your mind that you rarely ever visit."
我一直是诗歌的囚徒。
那时我太老了，现在反而年轻了。