So they built a system of canals to bring water down from the mountains.

VOA: special.2009.06.04

It only helps them to bring down the cost of health care, government has to operate the system more efficiently than the market does.

它只能,降低医疗的费用，政府必须,比市场更加有效地运作。

斯坦福公开课 - 经济学课程节选

But they have really had a big scaling down of the mass transit system this year.

但是今年确实大幅度削减了公共交通。

纽约的公共交通 - SpeakingMax英语口语达人

These are going to be fairly common-sense definitions, but they're important, and when you get to a problem set, really nailing down what the system is, not more, nor less, in terms of the amount of stuff, that's part of the system, it's going to be often very crucial.

这些是,很常识性的定义，但是很重要，当你要解决问题时，务必要搞清楚系统是什么，它包含多少物质，不能多也不能少，这往往,是非常重要的。

麻省理工公开课 - 热力学与动力学课程节选

Remember, because that 1 s orbital is all the way down in terms of if we're thinking about an energy diagram, we're all the way down here, so we have a huge amount of energy we have to put into the system in order to eject an electron.

还记得吧，因为1，s，轨道在能量示意图里,是在最底部的，我们要一直到最下面，所以我们要向这个系统注入非常大的能量,才能打出一个电子。

麻省理工公开课 - 化学原理课程节选