Some trees act as natural fertilizers.

VOA: special.2009.09.01

Sometimes you can design drugs that act like a natural ligand without being the natural ligand.

有时你能设计具有天然配体功能的药物,但它不一定和天然配体相同

耶鲁公开课 - 生物医学工程探索课程节选

But when you remember that the subject at hand is actually in some way sex, then you can begin to associate the Lady's image of this moderate consumption of natural wealth - with some version of -- if this makes sense -- some version of an act of sexual consummation.

但是当你们想起,现在讨论的话题其实是性，然后你们可以将这位女士,关于适量消费自然财富的形象,与一些版本--如果那有意义-,一些版本关于性圆满的行为联系起来。

耶鲁公开课 - 弥尔顿课程节选

The act said the purpose was to "conserve the scenery and the natural and historic objects and the wild life therein and to provide for the enjoyment of the same in such manner and by such means as will leave them unimpaired for the enjoyment of future generations."

VOA: special.2009.09.28