关于这个问题,请参考
《中学英语高频词详解词典》(金盾出版社):
……
however 表示转折,尤其用于谈及一个既成事实时,表示转折,其意为“可是”“仍然”等。可放在句首、句中或句末,通常用逗号与句子其他成分隔开。如:
My father, however, did not agree. 但是,我父亲不同意。
My room is small; however, it’s comfortable. 我的房间很小,但却很舒服。
He said that it was so; he was mistaken, however. 他说情况如此,可是他错了。
注意,however不能像 but(但是)那样直接连接两个句子(注意正句中的标点符号)。如:
我们都已尽了最大的努力,不过我们还是输了。
误:We all tried our best, however we lost the game.
正:We all tried our best, but we lost the game.
正:We all tried our best; however, we lost the game.
正:We all tried our best. However, we lost the game.
(3) 表示惊奇或强调,相当于how ever的用法,其意为“究竟怎样,到底以什么方式”。如:
However did you get here without a car? 没有汽车你究竟是怎样来的呢?
However does he manage to write music when he is so deaf? 他聋成这个样子,究竟是怎样从事作曲的呢?