随机实验是因果推理的黄金标准，但它们并不总是可行的。
"Randomized experiments are the gold standard for causal inference, but they are not always feasible."
The most expensive cost in free-to-play games is players' trust—once overdrawn, it can never be bought back.
The development of formal systems has revolutionized our understanding of mathematics.
Just because you make a good plan doesn’t mean that’s what’s gonna happen.