I think that's part of the frustration." DeAngelis says the strategy going forward must be to fight the battle on many fronts, building on the lessons learned from research,detection and treatment.

VOA: standard.2010.03.25

So the lessons to be learned, after years of watching this, is that the norm is change.

因此在观察许多年后，我发现了经验，改变是一种常态。

普林斯顿公开课 - 领导能力简介课程节选

So the lessons to be learned, after years of watching this, is that the norm is change.

因此在观察许多年后，我发现了经验，改变是一种常态。

普林斯顿公开课 - 领导能力简介课程节选