表示转折或对比
1) but表示转折,while表示对比.
Some people love cats,while others hate them.
2) not…but… 意思为"不是……而是……"not 和but 后面的用词要遵循一致原则.
They were not the bones of an animal,but of a human being.
3）although然而
I did not know that then,although I learned it later.
当时我不知道那件事,但我后来知道了.
4）however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.