Today,the species is on the verge of extinction.

VOA: special.2009.03.25

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。

耶鲁公开课 - 心理学导论课程节选

wouldn't there be extinction after a while?

在强化消失后是否也会发生消退？

耶鲁公开课 - 心理学导论课程节选

Some estimates suggest species extinction because of human activity is about 1,000 times faster than the natural rate of loss.

VOA: standard.2010.01.31

These conditions permitted a development of institutions and habits needed for freedom, even as they also made Europe vulnerable to conquests and to extinction, and Europe was almost extinguished practically before there was a Europe; very early in its history.

这些恰恰是自由的形成和发展,需要的的制度和特征,尽管这也使欧洲,在外敌入侵时变的不堪一击,实际上,在它早期的历史中,欧洲在尚未形成前就差点消失

耶鲁公开课 - 古希腊历史简介课程节选

"There are at least 27 different indigenous groups in Colombia that are considered to be at risk of extinction largely as a result of armed conflict and forced displacement.

VOA: standard.2009.03.22

Scientists warn that without an agreement to reduce so-called green house gas emissions, global temperatures will continue to rise, with the catastrophic consequences of extreme weather events, the spread of drought and disease, and the extinction of plant and animal species.

VOA: standard.2009.12.09