Emotions are biological signals that prepare the organism for action.

"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."

没有合适的人来实施，最好的技术也会失败。

从n对观测值的样本中获得的相关系数的可能误差是sqrt((1-r²)/(n-2))。