Perusing it, he was disturbed by the book's repeated use of the N word.

细读这本书时，他对书中反复使用的N字感到不安。

So one way to develop theme is through the repeated use of a symbol or an object.

因此，发展主题的一种方法是通过重复使用符号或对象。

The nonviolent response to that shifts the focus back to a different question - how to address the repeated police use of excessive force.

对此次事件的非暴力回应将焦点转移到另一个问题上——如何解决警察一再过度使用武力的问题。

This means that with repeated use, they have a reduced response to nicotine, and therefore an increased dose of nicotine is needed to achieve the original response.

也就是说长期吸烟，会让机体对尼古丁的反应越来越迟钝，因此需要摄入更多的尼古丁才能维持原有的效果。

To understand why opioids are so addictive, it helps to trace how these drugs affect the human body from the first dose, through repeated use, to what happens when long-term use stops.

要想了解阿片类药物为什么那么容易让人上瘾，首先就要追踪这类药物在各阶段对人体的影响，包括第一次使用时，反复使用之后， 以及长期用药后又突然停药时会发生什么。

Drugs have the power to alter the brain's chemistry, and repeated use can permanently rewire the neural networks that support our ability to think, make decisions, learn, and remember things.

药物有能力改变大脑的化学成分，重复使用可以永久性地重新连接支持我们思考、决策、学习和记忆能力的神经网络。