比较 rich and poor 与 rich or poor的用法：前者相当于名词，意为“穷人和富人”“贫富”；后者相当于副词，用作状语(表示让步），意为“不管是穷人还是富人”。如：

Times are hard for rich and poor alike. 这年头富人和穷人的日子都不好过。

There will be rich and poor for all eternity. 贫富将永远存在。

Rich or poor, they are all my friends. 不管是穷人还是富人，他们都是我的朋友。

另外，还要注意 between rich and poor 的用法：

With urbanisation the antagonism between rich and poor sharpened. 伴随着城市化的推进，贫富间的对立情绪也加剧了。

There's a chasm between rich and poor in that society. 那社会中存在着贫富差距。

The developed nations have to recognize the growing gap between rich and poor around the world. 发达国家必须认识到世界范围内的贫富差距正在不断扩大。

有时 rich and poor 用于名词前作定语。如：

Physical capital is a scarce resource in rich and poor countries alike. 不论是在富国还是在穷国,物质资本都是一种稀缺的资源。