Industrialized and developing nations have for two years been trying to come up with a workable framework for December negotiations in Copenhagen but with little to show for it.

VOA: standard.2009.09.28

We can see various breaks in financial history when some new idea was suddenly proven workable.

金融史上,当新的想法突然间变得可行,我们就能看到许多的创新突破

耶鲁公开课 - 金融市场课程节选