The Europeans also began discussing the broad outlines of future leadership posts for the European Union, once a reforming charter known as the Lisbon Treaty is fully ratified.

VOA: standard.2009.10.30

And, in fact, once you teach an animal something, if you stop doing the teaching the response goes away and this is known as extinction.

事实上，条件反射形成以后，如果得不到强化,条件反应就会逐渐消失,这就是消退。

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