The government would pay for the silver with paper money -- treasury notes -- which could be exchanged for gold or silver money.

VOA: special.2010.06.03

There's no change in them, and then we also looked at some at non-state functions, work and heat, and saw that those aren't zero going around a cycle. Of course you can do work in a cyclic process, and heat can be exchanged with the environment at the same time.

它们不会有变化，然后我们研究了,一些非态函数，功和热量，并看到,沿着循环行进一周的话,它们并不是零，当然你可以在,一个循环过程中做功，而同时热量可以在系统,与外界环境之间进行交换。

麻省理工公开课 - 热力学与动力学课程节选

SDRs,which are worth about $1.50 can be exchanged for the leading currencies, including the dollar, the euro and the yen.

VOA: standard.2009.04.20

"Now they are checked by Interpol. Before we did not have a communications system that allowed information to be exchanged rapidly around the world with all of our countries.

VOA: standard.2009.11.09

, I came to the mujahadeen and I told them everything and we arranged together this attack to make the Americans understand that the belief of Allah, that eman which we hold, the fatwah that we strive for cannot be exchanged for all the wealth in the world."

VOA: standard.2010.01.09