新概念英语
however与but
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.
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.
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.例如：
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.
however与although
1、although 是连词，意思是：尽管;虽然;但是;然而可以单独引领句子，并且绝大部分用在句首;
例句：Although he is known to only a few, his reputation among them is very great.尽管只有几个人知道他，但是他在他们之中的名声很大。
Although they're expensive, they last forever and never go out of style.尽管它们贵，它们永远耐用并且永不过时。
2、however 是副词：adv. 无论如何;不管怎样(接副词或形容词);然而;可是在however和although是同样的转折意思的时候，前者是副词，后者是连词，词性首先就不一样。当however做副词使用并且表示是转折意味的时候，不可以单独引领句子，必须是上文说了一件事情，however是承接上文所说的意思进行转折，可以用在下句的句首，并可以用逗号分开，也可以用在句中，前后用逗号分开。
This was not an easy decision. It is, however, a decision that we feel is dictated by our duty.这可不是一个轻松的决定。不过我们觉得我们有责任做出这样的的决定。
