一、副词用法
however作副词用时，表示“然而；但是”，可以位于句首、句中和句末；位于句首时，要用逗号与句子其它部分隔开；位于句中时，其前后都要用逗号；位于句末时其前用逗号分开。例如:
She felt ill.She went to work,however,and tried to concentrate.
她病了。然而她照旧去上班，并且尽力集中精神工作。
His first response was to say no. Later,however,he changed his mind.
他最初的反应是不同意，可是后来他改变了主意。
二、连词用法
however可以作连词表示“无论以何种方式，不管怎样”，引导让步状语从句。
You can travel however you like.
你可以随心所欲地去旅行。
However I approached the problem,I couldn’t find a solution.
这一问题我不管怎样都无法解决。
三、however和but对比
however与but 两者都做“但是，然而”讲，而且都引出并列句。从语义上看，but所表示的是非常明显的对比，转折的意味较however要强。从语序上看，but总是位于所引出的分句之首，而however却可位于句首、句中和句末，同时从标点符号上看，but之后一般不得使用逗号，而however则必须用逗号与句子其它部分分开。例如：
I thought those figures were correct. However,I have recently heard they were not.
我原以为那些数字正确无误，不过我最近听说并不正确。
