He goes back and redoes the calculation, only in this case he says what I am going to do is I am going to redo the calculation for helium, but I am going to consider not just the mass of the electron but the reduced mass of the system.

他回去重新做了计算，仅在这种情况下他才会说说我将要,为氦重做计算，但我认为,不只是电子的质量,还有系统质量的减少量。

麻省理工公开课 - 固态化学导论课程节选

The CDC can buy this from the manufacturer for a lower price, and when you hear about government organizations distributing vaccines to different parts of the world, they're buying at a reduced rate but it's still not inexpensive.

疾控中心可以从工厂拿到较低价格的疫苗,当你听到,政府组织向世界各地,分发派送疫苗时,他们确实给的是折扣价,但却并不那么廉价

耶鲁公开课 - 生物医学工程探索课程节选