`however` 是一个副词或连词，其基本含义是“然而”、“无论如何”、“不管怎样”。在句子中，它可以用来表达转折、让步或对比，连接两个相对立或不同的想法。

用法示例：

作为副词：

He is really good at playing the piano. However, he doesn't like it.

作为连词：

No matter how hard he tried, he couldn't solve the problem.

In the high-fear group, however, the brain area that was activated was different.

`however` 在口语中也非常常见，用来引入与前面内容相反或不同的观点。

希望这能帮助你理解 `however` 的意思和用法