The most important natural cause of fire is lighting.

自然界最主要的引火物质是闪电。

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Already in that day scientific thought dictated that there must be a natural cause and explanation for everything.

在那个时期，科学思想已经指出，世界必须存有能解释一切事物的一个自然起因。

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Now let's focus on a specific example of a natural predator that can cause a lot of damage to coral reefs—the Crown of Thorns, or CoT starfish.

现在，让我们来看一个自然捕食者的具体例子，它会对珊瑚礁造成很大的伤害——那就是刺冠海星。

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Natural disasters cause a great deal of hardship to those immediately affected by them.

FORBES: Despite $50B In Damages, Hurricane Sandy Will Be Good For The Economy, Goldman Says

And that fracking can cause natural gas to migrate into drinking water sources.

FORBES: China Closer To Joining Shale Gas Fracking Craze

Dr Sharma said the new seed has no trace of any of the natural chemicals which cause a narcotic effect - namely, morphine, codeine and narcotine.

BBC: Addictive-free poppy seed developed