At that age， I'd take any excuse to make estimates and do minor arithmetic. I'd calculate our gas mileage -- figure out useless statistics on things like grocery spending. I'd been hearing an ad campaign about smoking. I can't remember the details， but basically the ad said， every puff of a cigarette takes some number of minutes off of your life: I think it might have been two minutes per puff. At any rate， I decided to do the math for my grandmother. I estimated the number of cigarettes per days， estimated the number of puffs per cigarette and so on. When I was satisfied that I'd come up with a reasonable number， I poked my head into the front of the car， tapped my grandmother on the shoulder， and proudly proclaimed， "At two minutes per puff， you've taken nine years off your life！"

未来属于那些今天做好准备的人。

有时候，最小的事物占据了心中最大的空间。

但大多数股票的短期租赁者对确保公司治理专注于将股东的利益放在首位并不特别感兴趣。

工具变量的美妙之处在于它们让我们以新的视角看世界。