That means they're expensive. Last year,citing the cost, the Pentagon canceled a $14 billion program to buy new helicopters for the rescue squadrons and switch the medical missions to less heavily armed Army helicopters.

VOA: standard.2010.04.27

So what I want to do now is I want to switch course and introduce a new tool.

所以接下来我想换个话题了,我们来介绍一个新的理论工具

耶鲁公开课 - 博弈论课程节选

So I'm going to switch to a new tool.

所以现在我要介绍一个新的工具

耶鲁公开课 - 博弈论课程节选