These are married fathers who stay out of the labor force for at least one year, mainly so they can care for their family while their wives go to work.

VOA: special.2010.04.23

But, of course, we want to go all the way to distance, so we take the second derivative and we have this equation for force here.

当然我们最后想要的是距离,所以我们取二阶微,分就有这个式子。

麻省理工公开课 - 化学原理课程节选

They seem to be going somewhere and there's this sort of force of pull or gravity in music having to do with some chords wanting to go to other chords.

和弦向某一个方向发展，就像有一股力量拉着它们,或者说音乐的重力吸引着它们，让一些和弦想行进成为另一些和弦。

耶鲁公开课 - 聆听音乐课程节选