conj (1) 但(是)，可(是)(on the contrary)：My mother went，～I didn't.我妈妈去了，可我没有去。She doesn't like wine，～her husband does.她不喜欢酒，但她丈夫喜欢。We offered not a pledge～a request.我们没有给予承诺，而是提出要求。Not you～I am to blame.不怪你，应该怪我。

(2) 然而，但，却 (in spite of this/that; however; yet)：I ought to have helped her，～I never could.我本应帮助她的，可我一直没能帮上忙。She cut her finger badly，～didn't cry.她把手指割了一个大口子，却没哭。Life is limited，～there is no limit to learning.生命有限，学无止境。It is not cheap，～(it is) excellent.这不便宜，但很不错。It was a sunny～rather windy day.那天阳光明媚，但风太大。He worked hard～without any success.他很努力，却毫无成就。

(3) 但也，同时(yet also; at the same time)：He was tired～happy.他很累，但很快活。She was poor～proud.她很穷，很有骨气。The girl was sadder～wiser.那女孩更伤感了，同时也更懂事了。

(4) 就会，没有不……的(without it happening that; without it also being the case that)(用于某些否定词之后)：It never rains～it pours.不下雨则已，一下就是倾盆如注。Scarcely a day passed～I met her.我没有一天不碰见她的(几乎每天都碰见她)。I can never go to London～I remember my happy youth there.我每当去伦敦就会想起我在那里度过的幸福的青少年时代。

(5) (表示不同意，惊讶)(used in exclamation to show disagreement， surprise or astonishment)：“I'll give you ￡10.” “B～that's not enough”“我给你10英镑。”“那不够。” “It's time to go to bed， children.” “B～we don't want to!” “孩子们，该睡觉了。”“可我们不想睡!” “He is getting married.” “B～that's wonderful news.”“他要结婚了。”“啊，那可是好消息。”

(6) (引入新话题)(showing that one is changing the subject)：B～now to our next question.现在说下一个问题。B～now we'd better get down to business.现在我们还是干正事吧!

but that 1) 要不是：He would have said no～(that) he was afraid.要不是害怕，他早说不同意了。 2) (等于that)：I don't doubt/question/deny～(that) you are surprised.我毫不怀疑/怀疑/否认你是吃惊了。 There's no doubt/question～(that) it was he who was guilty.毫无疑问是他有罪。 Who knows～that what he says is true? 谁知道，他说的话也许是真的?

but then 然而，再说：I like living here —～then I've never lived anywhere else.我喜欢住在这儿，可话说回来，我也从没有在别的地方住过。

not only ... but (also) 不但……，而且……：Not only beginners， ～also experienced craftsmen may learn much from this book.不仅初学者，就是有经验的工匠也能从他的书中学到许多东西。

prep 除了(去)(apart from; other than; except(for))(用在否定词no， nobody， no one， none， nothing， nowhere;疑问词who，whose，what，where以及all， everyone，anyone，everything，anything，everywhere，anywhere 等之后)：There was no direct route～through the centre of town.除了穿过市中心，没有直的路线。No one replied～a boy.除了一个男孩外，没有人答腔。There was nothing to do～(to) wait.毫无办法，只有等了。They did nothing～complain.他们光是抱怨。You can find this nowhere～in England.只有在英国你才能找到这个。Who～a fool would do such a thing? 除了笨蛋，还有谁会干这种事? Whose fault is it～hers? 不是她的错，又能是谁的? What should I find～an enormous spider! 我找到的竟然是一只大蜘蛛! All had fled～her (or All～she (her) had fled).除她之外所有人都跑了。Everyone was there～him(or Everyone～he (him) was there). 除了他，每个人都在那里。She looks anything～well.她的气色一点也不好。Put it anywhere～on the floor.除了地板上放哪儿都行。

the first/last/next but one (two)正数/倒数/接着第二(三)个： He lives in the last house～one in this street.他住在这条街上倒数第二座房子。

but for 要不是：B～for the fog， it might have been a pleasant day.要不是有雾，那一天本来可以过得很愉快的。B～for him all would have been lost.要不是他就什么都完了。

adv 仅仅，只是，刚刚(only; merely)(fml)：He was still～a child， when his mother died.他母亲死时，他还只是个孩子。This is～one case in many.这仅仅是许许多多之中的一例。There is～one man for the job.只有一个人适合做这个工作。We can～try. 我们只能试一试。I saw him～a few minutes ago.几分钟以前，我刚见过他。

all but 几乎：It is all～complete/finished.差不多完成了。He all～died of his wounds.他差点儿受伤致死。

can not but 只能：He could not～admit it.他只有承认这点。I could not～laugh.我忍不住要笑。

pron 没有……不…… (that...not; who...not)(用于某些否定词之后)：Not a man/No one～(= who doesn't) knows that.没有人不知道那件事的。There is no tree～(= that doesn't) bears some fruit. (prov) 没有不结果的树。

【辨异】1) but与however、nevertheless、still¹ 和yet都表示前、后两句在意义上的对立，都置于第二句之首。区别在于：首先，此时的but是连词，其前用逗号;此外，除连接句子，还可连接句子成分;而其他几个此时都是副词，其前用分号。语义上，but只是一般地表示前后语义相对立，如：We are going，but we shall return. (我们要走了，但还要回来的。) however(不过，然而)的对立意义不明显，主要强调后句，以与前句意义对比，如：We are going; however(“notice this also”)， we shall return. (我们要走了，然而，我们是要回来的。) nevertheless(虽然如此，不过，然而)含有让步意义，强调这点不可忘记，如：We are going; nevertheless(“do not forget that”)， we shall return. (我们要走了，尽管如此，我们可是要回来的。) still¹ (然而，虽然如此)强调后一句的内容是可能的，甚至是不可避免的，如：We have to go on foot; still (“it is possible or possible that”)， we'll get there. (我们只好步行，然而，我们会走到的。) yet (然而，却)强调另一种结果的可能性，如：We are going; yet (“in spite of all， someday”) we shall return.(我们要走了，然而，我们会回来的。) 2) but与except和save 都可用作介词，都表示“除了……外”，故都可用于下句中：We're all here but/except/save Mary. (除玛丽外，我们都在这里。) 区别在于，but 只用于no等否定词、who等疑问词及all和带every、any的词语后，而except和save(正式用语，古体)则无此限制，故下句中可用后两者，不可用but：The window is never opened except/save in summer(这窗子除了夏天从不打开。)此外，except和save后只能用宾语，而but后，如果代词看上去起主语作用，其后跟有谓语动词时，也可用主格，如：No one but he (or him) is wrong. (只有他一个人不对。) 3) but for与except for都可表示“要不是”的意思，且都是与虚拟语气连用，如：But/Except for you， I should be dead by now. (要不是你，我现在就不在人间了。) 不同处在于except for还可表示“除了……外”，与陈述语气连用，如：Everyone was there except for you. (除了你，大家都去那里了。)