“however”和“but”有什么异同？

1、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；位于句末时,  其前用逗号分开。

【例句】：She felt ill. She went to work, however, and tried to concentrate. 

【释义】：她病了。然而她照旧去上班，并且尽力集中精神工作。 

2、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。

【例句】：His first response was to say no. Later, however, he changed his mind. 

【释义】：他最初的反应是不同意，可是后来他改变了主意。 

3、however的其它用法： however可以作连词(conj.)，表示“无论以何种方式，不管怎样”，引导让步状语从句。

【例句】：I thought those figures were correct. However, I have recently heard they were not.

【释义】：我原以为那些数字正确无误，不过我最近听说并不正确。

【双语例句】：

1、You can travel however you like.

【释义】：你可以随心所欲地去旅行。

2、However I approached the problem, I couldn’t find a solution.

【释义】：这一问题我不管怎样都无法解决。

3、Learning the guitar isn't difficult， but you will have to practise.

【释义】：学弹吉他并不难，但是你得练习。

4、However， we need not do that now. 

【释义】：可是，我们现在不需要做那个。

5、 His friends， however， had other ideas. 

【释义】：然而他的朋友们却另有见解。