■ but

1) but 与 although (though) 能否同时出现的问题，见 although 条。

2) 在 although 条中已经谈到了，用主从连词 although 引入让步从句时，主句不能用 but 引入，因为 but 是个并列连词，加进去就会把主句降格为并列句的第二个分句，全句就成了不伦不类的一个让步从句加一个并列分句。but 因为是并列连词而不是副词，所以只能放在分句的句首，后面不能停顿（书面上不能加逗号），它前面同前一句的分隔，只能用逗号，不能用分号 (;)。反之，意义上同 but 相同但词性不同的副词 however, nevertheless, nonetheless 等，就可以与 although (though) 一起出现，本身可以放在主句的句首，后面一定要有停顿（书面上加逗号），也可以插在主句之中（前后加逗号）。如果前面的从句去掉 although (though)，主从句就变为并列句，但后一分句句首的 however 同前一分句之间，不能用逗号连接，而应该改用分号。这就形成了下面几个意义相同但结构不同的句子（注意标点）：Although I wanted to study, I was too tired. I wanted to study, but I was too tired. I wanted to study; however, I was too tired.

3) sorry 后面的 but，见 sorry。

4) but 还有一个许多词典上没有提及的很独特的语法功用，就是作为一个否定词引入一个定语从句，将这个从句的内容加以否定。这个作用，有点像介词 without。在其他一些欧洲语言，都有相当于 without + that 从句的结构，唯独英文 without 后面不能引入 that 从句。这个作用，在比较小的范围内由 but 来弥补。这样的结构，由于英文没有 without that 的结构，就相当于 without + X + -ing。

• Not a day passed by but he repented of what he had done. = Not a day passed by without him repenting of what he had done.没有一天他不忏悔自己做过的事。
• I never go past the theatre but I think of his last performance. = I never go past the theatre without (my) thinking of his last performance.我没有一次经过那剧院时不想到他那最后一次的演出。
• Not a day goes by but (that) I think of her. = Not a day goes by without my thinking of her.我没有一天不在想念她。
• It never rains but it pours.不下则已，一下就倾盘大雨。

这样的句子，有一个特点，就是主句通常都是否定句，再加上从句的否定，形成否定＋否定＝强意全部肯定。

5) 但是 but 的这个特殊用途还发展到同前面的 so 相呼应，形成 so (such)... but...结构，意义上相当于 so (such)... that... not... 而且这样的句子也都是“否定＋否定＝（强调）全部肯定”。

• Nothing is so bad but it might have been worse. = Nothing is so bad that it might not have been worse.没有什么事情会是坏到不可能更坏的。
• No one is so old but he may learn. = No one is so old that he may not learn.谁都不会老到不能学习的地步。
• No man is so great but he has his weak side. = No man is so great that he does not has his weak side.谁都不会伟大到没有弱点的地步。
• He is not so sick but he can come to school. = He is not so sick that he cannot come to school.他还没有病到不能来上学的地步。
• He is not such a fool but he knows it. = He is not such a fool that he doesn't know it.他还没有笨到连这个也不懂。
• Nothing is so beautiful but it betrays some defect on close inspection. = Nothing is so beautiful that it does not betray some defect on close inspection.没有什么东西会美丽到即使走近细看也不暴露出某种缺陷的地步。

6) but 的特殊用途，还沿另外一个方向发展，“兼任”that（或 who）和 not 双重角色，但这里的 that 同 5) 中与 so 相呼应的 that 不同，不是连词（连词引入的从句中应该有另外一个词作为主语），而是关系代词（在从句中作主语），同时又对从句的内容加以无形的否定。这样的句子，也都是“否定＋否定＝强意全部肯定”。

• There is no rule but has some exceptions. = There is no rule that doesn't have some exceptions.没有毫无例外的规则。
• There is no one but loves his own country. = There is no one who doesn't love his own country.没有不爱自己祖国的人。

7) but 的特殊用途，还有一个方向，就是 but that 可以形成一个连词词组，表示“要不是…的话”，指的是“假如过去已经发生的某事没有发生的话”，从句谓语动词用直陈语气的一般过去时，形式上肯定而其实否定；主句则用虚拟语气的完成时。

• She would have fallen but that he caught her. = She would have fallen if he hadn't caught her.要不是他扶住了她，她当时本来会摔倒的。
• I would have come but that I was sick in bed. = I would have come if I had not been sick in bed.我要不是卧病在床，本来就来了。

8) but 的又一个特殊用法，是在 deny, doubt, question, wonder 等有负面意义的动词的否定形后面加强“否定＋否定＝肯定”的语气。

• I don't deny but that he will succeed.我丝毫不否认他会成功。
• I will not deny but that there are innumerable errors in the rest of Descartes' works.我丝毫不否认笛卡尔其他作品中有许多错误。

由于这个 but 在此只是加强语气，所以用或不用都不影响根本文意，例如在林肯同政敌道格拉斯的论战中，道格拉斯 1858 年 8 月 21 日反驳林肯时有一段话说：

• He (Lincoln) does not deny but that that principle was unanimously adopted by the Republican party; he does not deny that the whole Republican party is pledged to it; he does not deny that a man who is not faithful to it is faithless to the Republican party; and now I want to know whether that party is unanimously in favor of a man who does not adopt that creed and agree with them in their principles.他并不否认，那个原则是共和党所一致采纳的；他并不否认，整个共和党都是发了誓要坚持那个原则的；他并不否认，不忠于那个原则，就是不忠于共和党；那么我现在想知道，一个人不采纳那个信仰，不同意他们的原则，那个党是否一致支持他。

类似这样用法的，还有 but that 前面有作为名词或动词而被否定的 doubt，而 but 则只是起加强语气的作用。

• There is no doubt but that he is the greatest painter of this century.毫无疑问，他是本世纪最伟大的画家（but 完全可以删去）。

美国法院的判决书中，there is no doubt but that...（毫无疑问，…）这个词组出现率很高。That 还常常可以略去。

• I don't doubt but he'll do it.我毫不疑问他会这样做。
• ... nor do we doubt but our reader... will concur with us. (Henry Fielding, Jonathan Wild)…而且我们也不怀疑，我们的读者…一定会同我们一致。

Question 前面有 no 或 little 等否定词，后面有 but that，这个 but 也只是起加强语气的作用。

• There is no question but that there will be a general rise in wages in the next month or two.(Edwin A. Lahey, New Republic, Oct. 1, 1945)毫无问题，往后一两个月，工资会普遍提高。

9) but 另一个特殊用法，是 I have no idea but [that]…，表示…“说不定”、“也许”。

• I have no idea but they will insist upon the whole amount being paid.说不定他们会坚持要求全额支付。
• I have no idea but it seemed like the right thing to do at the time.当时那样做，看起来也许是做对的。

10) but 又一个特殊用法，是 Who knows but (that)... ? 意思也是“说不定”、“也许”，从句的内容肯定或否定同语言形式一致。

• Who knows but that he may go?他说不定能去。
• Who knows but that everything will come right?事情会一帆风顺也说不定。
• When I play with my cat, who knows but that she regards me more as a plaything than I do her?当我同我的猫玩耍的时候，我把它当作玩物，但说不定它更加把我当作玩物呢。

1911 年，美国有一起杀人案，四名被告被判绞刑，其中三人还不满二十岁，判决书上说明如此重判的理由，一连用了四段以 Who knows but that... 开始的问句，说明以此判决震动社会，产生“亡羊补牢”效应。其中第三句较短，是：Who knows but that, as a result of this shock to the public conscience, the vicious dance halls will be wiped out? 说不定经过这次对公众意识的震动，可以把那些诲淫诲盗的跳舞厅一扫而光（译成中文似乎以不能译成为问句为宜）。

11) but 另一个特殊用法，是 It was impossible but (that)... ，以 but 来否定后面从句的内容，加上前面的 impossible，形成“否定＋否定＝强意肯定”，表示过去的“不可能不”，亦即“一定是”。

• It was impossible but they must have observed it.他们不可能没有观察到这一点。
• It was impossible but that the vast mass of the icebergs must have been subjected to climateric influences; ruptures must surely have taken place at some points.冰山的巨大质块一定已经受到过气象变化的影响；某些地方肯定发生过断裂。

12) 表示“不是 A 而是 B”，这个“而”虽然不是“但”，英文也要用 but 来表示 (not A, but B)。

• It is not red, but black.它不是红的而是黑的。

但是如果先说肯定的 B，再说否定的 A，两者之间就不用 but 而用 and 来连接（and 之前没有逗号）。例如前句可以改为：It is black and (*but) not red. 又例如：

• He did what his father told him to do and (*but) not he himself thought best.他父亲叫他做什么，他就做什么，而不是他自己觉得做什么最好就做什么。

也可以分成两个并列的小句（但要重复谓语动词），否定在前，肯定在后，不用 but。

• He doesn't drink coffee, he drinks tea.他不喝咖啡，他喝茶。

如果 A 和 B 不涉及谓语动词，也可以先说 B，再说 A, 不用 and。

• Mary, not George, was admitted.玛丽而不是乔治被录取了。

但如果先说 A，再说 B，就要用 but。

• Not George, but Mary, was admitted.