Speaking of up-and-coming jazz ensembles,10 bands were selected for a U.S.State Department world tour.

VOA: standard.2009.12.25

Now, instead of talking about individual particles, we talk about ensembles of particles.

现在，我们不讨论单个的粒子，我们讨论粒子群。

麻省理工公开课 - 固态化学导论课程节选