one another; another one辩识

one another是固定搭配，相当于each other,意为"互相"，在句中常用作宾语。例如：

We must help one another. 我们必须互相帮助。

another one意为"另外一个；再一个"。例如：

I don't like this sweater. Please show me another one. 我不喜欢这件毛衣，请再给我拿一件看看。

Would you like another one?再来一个吗？