Democrat Carolyn Maloney asked him about economist's predictions that it would take the country to full employment: "Assuming that jobs are created at 2.8 million jobs per year, the best job creation of any administration, and this was achieved by former President Clinton, how long would you expect it to take us to get back to full employment?" "Well,without offering an opinion on that 10.7 million jobs, at that rate though, it would be about three years."

VOA: standard.2009.12.05

As time increases, the angle increases and we can ask, "How long does it take for the particle to come back to the starting point?"

这个角度随着时间在增加,我们会问,"质点需要多长时间,才能转到起点"

耶鲁公开课 - 基础物理课程节选