Even some military equipment requires rare earth elements.

甚至有些军事装备也需要稀土元素。

It requires an element that doesn't exist on Earth.

它需要一种地球上不存在的元素。

This poor girl of nineteen already required some element of spiciness in order to get up an interest in a novel.

这个十九岁的可怜女孩已经需要一些辣味来引起对小说的兴趣。

If we examine the details of any actual instance of the trade cycle, we shall find that it is highly complex and that every element in our analysis will be required for its complete explanation.

如果我们检查贸易周期的任何实际实例的细节，我们会发现它非常复杂，我们分析中的每个元素都需要对其进行完整的解释。