but 和however 有什么区别？如句中：I've come to the conclusion that the people who are trying to save the world are probably quite sincere about it, but they dont't know ...其中but可以换成however 吗？
所以因为they前没有逗号所以不能用however来换？
辨析 however和 but 二者都意为“可是，但是”； but是并列名词，连接两个并列分句，上下二句在总的意义上构成了对比。 I really don't like cheese, but I will try just a little this time.我实在是不喜欢吃奶酪，但是这次我要尝一点。 however不能直接连接两个分句，必须另起新句，并用逗号隔开。 It was raining hard. However, we went out to look for the boy. 雨下得很大，不过我们还是出去寻找那个孩子but 口语常用词，语气较强，泛指与前述情况相反。 however ...
1、but 副词This took him but a few minutes. 这仅仅花他几分钟时间。 She is but a child. 她不过是一个孩子罢了。 I can but hear. 我只能听听而已。 If I could but see him! 我要是能见一见他就好了! I can but try it. 我好歹试试看。 He le...
