How do you determine policy when you don't have the hard scientific facts and when a public health threat is probable but not certain?

如果不掌握确凿的科学事实，而公共卫生威胁很可能发生但并不确定，则如何来决定政策？

youdao

He philosophized, he admitted, not because he was certain of establishing the truth, but because it gave him pleasure.

他承认自己反复推究不是因为他确定找到了真理，而是因为那给了他很多乐趣。

《柯林斯英汉双解大词典》

If you've always been a certain way or done a certain thing, but it's not working for you any more, or you're not content, Emerson says that it'd be foolish to be consistent even with our own past.

如果你总是以某种方式或做某种事情，但它不再适合你，或者你不满足，爱默生说，即使是与我们自己的过去保持一致也是愚蠢的。

youdao

"We will not only defend ourselves to the uttermost but will make it very certain that this form of treachery shall never again endanger us ...

VOA: special.2011.06.02

So the writer seems very determined to tell the story in a way that depicts God as acting not capriciously but according to certain clear standards of justice.

作者似乎决定,描述不是一个变幻莫测,而是有着很清楚公正原则的上帝。

耶鲁公开课 - 旧约导论课程节选

But there's more, and this is why novels are long: - not too long, not too short, but of a certain length-- of a certain magnitude, as Aristotle puts it.

但是当然还有很多别的东西，要不这本书也不会那么长：,不是太长，但也不短，刚刚好能说明清楚问题的长度-,亚里士多德这么评价。

耶鲁公开课 - 文学理论导论课程节选

It is likely, but not certain, that Mr Ecevit will again become prime minister.

ECONOMIST: Marking time

Irish Justice Minister Alan Shatter told RTE Radio it was "probable but not certain" the car found burnt-out was used in the police officer's murder.

BBC: Cross-border criminal gangs discussed by MLAs in assembly

But it is not certain that he wants to manage his father's large and hard-to-handle collection of media assets.

ECONOMIST: Family businesses