Republican leaders in the U.S.Congress responded to the president's remarks by charging once again that he wants a health care system run by bureaucrats in Washington.

VOA: standard.2009.06.15

Once the gases are mixed, there's not going to be any further net change in the system.

一旦气体混合,这个系统就不会发生任何净的变化。

麻省理工公开课 - 热力学与动力学课程节选

"The more people we can get on the roads with bikes the better." There will be 6,000 bikes available, and the mayor hopes once it gets rolling, this system will result in 40,000 bike trips a day.

VOA: standard.2010.07.30