The big question for American now is whether there will be light at the end of the tunnel after more than 8 years of war there, after all that life lost and fouture spent.

现在对于美国一个重要的问题就是,是否有曙光的出现,8年的战争中，美国政府花费了大量的金钱，很多人也因为战争也失去了生命。

普林斯顿公开课 - 国际座谈会课程节选

For example, if you started here and you did all this and you came back here, the average velocity would be zero, because you start and end at the same value of x, you get something; 0 divided by time will still be 0.

例如,如果你从这里开始运动,经过这个过程又回到这里,平均速度就是0,因为初态和末态的位移相同,你得到了什么呢,0除以时间还是0

耶鲁公开课 - 基础物理课程节选