But,she warns this progress is fragile. She says the momentum for health development could come to a grinding halt because of problems stemming from the food and financial crises, the changing climate and the H1N1 influenza pandemic.

VOA: standard.2009.12.29

But we all know that the reason things come to a halt when you push them is, there eventually is some friction or drag or something bringing them to rest.

但我们都知道,推完之后会停下来的原因就是,最后还是有某种摩擦或者拖拽,或者别的什么使得物体静止下来

耶鲁公开课 - 基础物理课程节选

But we all know that the reason things come to a halt when you push them is, there eventually is some friction or drag or something bringing them to rest.

但我们都知道,推完之后会停下来的原因就是,最后还是有某种摩擦或者拖拽,或者别的什么使得物体静止下来

耶鲁公开课 - 基础物理课程节选