But in Washington the rating system is not governed by the labor contract with the teachers union.

VOA: special.2011.08.11

Maybe it's not always the raider; it's that some employees had trusted in an implicit contract that they were offered by their employer.

也许也不都是这些公司蓄意收购者；,也许是一些雇员相信了他们雇主给他们的,暗示性承诺。

耶鲁公开课 - 金融市场课程节选

All right, so it might be that again, the problem with enforcement, although actually in 1880 America, it's not clear that they couldn't have enforced that contract.

好的,但是我刚才说了强制性的问题,虽然说那是1880年的美国,当时这种合同是否违法没有明确的界定

耶鲁公开课 - 博弈论课程节选

So if you get the CD set, not only do you get a wonderful beginning library of classical music but in effect you get a lifetime service contract with it.

所以一旦你买了整套CD,你不仅可以拥有一个古典乐图书馆,而且还可以享受终身服务

耶鲁公开课 - 聆听音乐课程节选