"We've only had this technology around for about fifteen years, and most carcinogens will take about several decades, thirty-forty years to develop a cancer.

VOA: special.2011.06.06

The only history that you would have had fifteen years ago would have been those funds that produced great returns, so it's all identified after the fact.

你只会看到在这15年的历史数据中,所有对冲基金都有着极佳的回报,这都是事后调整确认的

耶鲁公开课 - 金融市场课程节选

Alan Shepard made only a fifteen-minute flight in the little one-man Mercury spacecraft.

VOA: special.2009.07.08

Shepard's flight lasted only a few seconds longer than fifteen minutes.

VOA: special.2009.06.17