在英语日常的学习表达中,表示转折或对比的连词有but、yet、however、nevertheless等等:

1.but作为连词的意思有:但是、通常用not...but...而是、可是,然而、表示惊讶、 (用来加强语句重复部分的语气)一定、 (用来引入新话题)那就、(常用于否定句)而不;若不、(用于含doubt,question等字的否定句中,相当于that)对于。
He tried hard but he was unsuccessful. 他做了很大努力但没有成功。下面是but的几种习惯表达:
1)not...but..."不是 ...而是...",连接两个并列成分。
Victory is not the end but a phase to the end.
2)but for=without "要不是,如果没有" ,相当于虚拟条件句
But for the rain ,we would have a pleasant journey.
3)but that =except that "若非,要不是",引导虚拟条件句
He would have helped me but that he was short of money.
4)but then =on the other hand "不过,在另一方面"
5)all but "除。。。之外都,几乎"
His theory is all but correct.
他的理论几乎是正确的。
6)anything but "决不"
She is anything but beautiful .
她根本不漂亮。

2. yet作为连词意思是,然而;但是。
The car was old, yet it was in excellent condition. 这辆车子很旧,但仍处于良好的状态。
下面是yet的习惯搭配词组
not yet尚未,还没有
yet awhile(用于否定句)还要一段时间,还要一会儿
yet once more再一次
and yet 然而,但是,可是
another and yet another 一个又一个的,接二连三的
as yet 现在还,到目前为止; 到那时为止; 至今
but yet 但还是,可是还
just yet 恰好现在
more and yet more 更要,多而再多
nor yet 也不

3. however
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。

4. nevertheless
I don't know anything against that man; nevertheless I don't trust him. 我对那个人没有什么不良的看法,但我不能信赖他。