粗糙关系数据库模型从本质上来说就是多值信息系统，它继承和扩展了经典的粗糙集理论，但与经典粗糙集理论又有着很大的不同。

Rough relational database model is Multi-valued information system essentially, inheriting and extending classical rough sets theory. But there is much difference between them.

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It was a classical model, right, so we could say the electron is exactly this far away from the nucleus.

这是个经典模型，对吧，我们说电子离,原子核就是这么远。

麻省理工公开课 - 化学原理课程节选

And, in general, the idea of what goes on in classical conditioning is that the response is sort of a preparation.

一般认为，在经典条件作用中,反应就是某种准备过程。

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The classic moral hazard problem is the problem that you give fire insurance on a house and someone burns down the house in order to collect the insurance.

有个经典的道德风险的例子就是,给一栋房子投保了火险,有人就可能会烧了这栋房子,以获得保险赔付

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