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。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。
1、but和however区别例句
(1)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。
(2)Eat to live , but do not live to eat.吃是为了活，不要活着为了吃。
2、however的用法
1.however作副词用时，表示“然而；但是”，可位于句首、句中和句末；位于句首的时候，要用逗号和其他句子部分隔开；位于句中的时候，其前后都要用逗号；位于句末的时候其前用逗号分开，例如：
(1)She felt ill.She went to work,however,and tired to concentrate.她生病了。然而她仍去上班，并且尽力集中精神工作。
(2)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。
2.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。例如：
(1)You can travel however you like.你可以随心所欲地去旅行。
(2)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。
