however，no matter how
However和no matter how同义，都表示“无论如何”的意思，又都引导让步状语从句，但它们的修辞意味和使用场合有所不同。
However是比较正式的用语，大都用于书面语，口语中较少使用；no matter how则比较口语化，它的语势比however重，故常用在强调的场合。请看下面的例句：
The task must be done，however arduous it may be．
无论多么艰难，这个任务一定要完成。
（试比较一般句：The task must be done though it is arduous．）
I ll take your words，no matter how harsh they may be．
无论语气多么难听，我还是听你的话的。
（试比较一般句：Although your words are harsh，I ll take them．）
However有时可表达“然而”、“可是”之意，出现于句中或句尾。例：
They said that it was so；they were mistaken，however．
他们说事情就是如此，可是他们错了。
与之类似区别的词语很多，例如whatever/no matter what、whenever/no matter when、wherever/no matter where、whichever/no matter which、whoever/no matter who.