科罗拉多大学的鲍尔奇教授说，与此同时，人们一直把火当作一个需要完全控制且只有在必要的情况下才会让其释放的事件。

At the same time, people continue to treat fire as an event that needs to be wholly controlled and unleashed only out of necessity, says Professor Balch at the University of Colorado.

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这样的计划是非常必要的，因为在许多干旱地区，我们并不清楚其地下水资源的范围。

Such programs are much needed because in many arid lands there is only a vague idea of the extent of groundwater resources.

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她认为没有必要闪烁其词。

She saw no reason to prevaricate.

《柯林斯英汉双解大词典》

She speaks of the necessary unity of body and soul, which for her entails a defense of the body, defending, as she does, its knowledge and its goodness.

她说道身体心灵结合的必要性，这对她来说需要保卫其身体，为身体的知识与美好抗击。

耶鲁公开课 - 现代诗歌课程节选

I want to talk about this regime a little bit now what Aristotle understands to be the requirements or the fulfillments the necessities of this aristocratic republic.

我现在要来谈谈这种政体,在亚里士多德的理解下,什么是这种贵族共和的必备条件,其实现与必要性。

耶鲁公开课 - 政治哲学导论课程节选