但是
但是无论如何，在这里however 是做为副词修饰后面的形容词的，例如：she wants just one thing in life:her boss,but however hard she was tries,this keep on going wrong for her.(all i want原版小说例句）
然而
应该是出现在日常口语中的，表转折的“但是，然而”
书面不能用的哦
but和however都有 “但是”的意思，可以表转折。
但是他们的用法略有不同，
however 用在逗号的前面。
例如：i konw you are a good boy but i don't love you.
i konw you are a good boy.however,i don't love you.
基本上简单来区分就是那个逗号了。
补充一点的是，however 还有无论如何的意思。
but 和however如果同时表示 “但是”的意思是不能连在一起用的。
希望我的答案能够给你帮助。
however:
连接词 conj.
1.然而,可是,不过
i feel a bit tired. however, i can hold on.
我有点累了,但我能坚持下去。
副词 ad.
1.无论如何,不管怎样
however hot it is, he will not take off his coat.
无论多热,他也不会脱掉外衣。
2.不管用什么方法
however he tries, he never seems able to work satisfactorily.
不管他怎么努力,他好像总不能令人满意地工作。
3.究竟怎样,到底如何
however did you know that?
你到底怎么知道那件事的?
but:
连接词 conj.
1.但是
it is hot in summer here, but it is not cold in winter.
这里夏天热,但冬天不冷。
2.(通常用not...but...)而是
our purpose is not to do it for you but to teach you to do it by yourself.
我们的目的不是替你做这事,而是教会你自己来做。
3.可是,然而
she looks very young, but she is already in her 30's.
她看上去很年轻,可是她已三十多岁了。
4.(表示惊讶、不同意等)喔,哇
heavens, but it snows.
天哪,真的下雪了。
5.(用来加强语句重复部分的语气)一定
we will be here on time. but on time.
我们将准时到达这里,一定准时。
6.(用来引入新话题)那就
but now to the last question.
现在就来谈最后一个问题吧。
7.(常用于否定句)而不;若不
but that i saw it, i wouldn't have believed it.
若不是亲眼目睹,我还不会相信呢。
it's not so high but we can jump it.
它并非高到我们跳不过去的地步。
8.(用于含doubt,question等字的否定句中,相当于that)对于
there is no doubt but he won.
对于他获胜这一点没有疑问。
介词 prep.
1.(用于nothing,nobody,who,all等词后面)除...以外
no one saw it but me.
除了我没有人看到。
dick seldom talks of anything but music.
迪克很少谈及音乐以外的事情。
副词 ad.
1.只,仅仅,才
it took her but a few days to learn it.
只不过几天时间她就学会了。
2.【美】【俚】(用来加强语气)肯定地,绝对地
go there but fast!
赶快到那儿去!
代词 pron.
1.(关系代词,相当于who...not,which...not)没有...不
not a man but felt it.
没有人不感觉到它。
名词 n.
1.用"但是"来表示反对;异议[c]
not so many buts, please.
