英语连词的用法和总结(全)

英语连词用法和总结一、概述2二、并列连词的用法2(一)、表示转折关系的并列连词2(二)、表选择的并列连词6(三)、表示因果关系的并列连词7(四)、表示并列关系的并列连词9三、从属连词的用法11(一)、引导时间状语从句的从属连词11(二)、引导条件状语从句的从属连词13(三)、引导目的状语从句的从属连词16(四)、引导结果状语从句的从属连词16(五)、引导原因状语从句的从属连词17(六)、引导让步状语从句的从属连词19(七)、引导方式状语从句的从属连词21(八)、引导地点状语从句的从属连词21(九)、引导比较状语从句的从属连词21(十)、引导名词从句的从属连词等22四、并列连词词组的用法22(一)、bothand的用法22(二)、eitheror的用法22(三)、neithernor的用法23(四)、not onlybut also的用法23(五)、not onlybut also和对称结构24五、连词总结26一、概述连词是一种虚词，用于连接单词、短语、从句或句子，在句子中不单独用作句子成分。连词按其性质可分为并列连词和从属连词。并列连词用于连接并列的单词、短语、从句或句子，如and, but, or, for等；从属连词主要引出名词性从句(主语从句、宾语从句、表语从句等)和状语从句(时间状语从句、条件状语从句、目的状语从句等)，引出名词性从句的连词如that, whether等，引出状语从句的连词如when, because, since, if 等。二、并列连词的用法(一)、表示转折关系的并列连词。主要有 but(但是), yet(可是), while(而，却)等。如：I would have written before but I have been ill. 我本该早写信的，但我生病了。I have failed, yet I shall try again. 我失败了，但我还要尝试。You like tennis, while Id rather read. 你爱打网球，但我爱看书Someone borrowed my pen, but I dont remember who. 有人借了我的钢笔，但我不记得是谁了。He said he was our friend, yet he wouldnt help us. 他说他是我们的朋友，但却不肯帮助我们。but的用法举例1. 连接词或短语It was a sunny but not very warm day. 那一天天气晴朗，却不太暖和。He drives not carefully but slowly. 他开车不是很小心，而是开得很慢。2. 连接句子This isnt a good one but it will answer. 这不太好，但可以将就用。He looks honest, but actually hes a rogue. 他看起来很老实，实际他是一个坏蛋。She has had no answer to him but he gave no answer. 我向他说了早上好，但他没有回应。The ice remained, but there was no water underneath. 冰还在，但下面却没有水。Mrs. Brown was about to begin, but Jennie spoke first. 布朗夫人正要开始讲话，珍妮先讲了。At first he was a little shy, but now he acts more natural. 开始时他有些腼腆但现在他表现得很自然了。There was a little trouble at first, but things were soon quiet. 起初有点小麻烦后来情况就平静了。3. 用于句首But that question doesnt arise. 但没发生那个问题。But in secret she was delighted. 但她暗中感到高兴。But what else can we do? 我们还能做什么?But in the end he gave in. 但最后他还是让步了。But theres one thing we are agreed on. 但有一点大家的意见是一致的。4. 用于道歉的表达之后Sorry, but were behind schedule. 抱歉，我们落在计划后了。Im frightfully sorry, but I cant see you today. 太对不起了，我今天不能见你。Excuse me, but I dont think thats quite true. 很抱歉，我认为这与事实略有出入。5. 用于notbut，表示“不是而是”Not you but I am to blame. 不是你的错而是我的错。6. 用在某些否定语后，表示“只”： He eats nothing but hamburgers. 他只吃汉堡包。She knows no one but you. 她只认识你。You have nobody but yourself to blame. 只能怪你自己。No one but me saw her. 只有我看见他(from )。7. 用于next (last) but one 中，表示“隔壁再过去”“倒数第”He lives in the next house but one. 他住在隔壁再过去一家。He was the last but one to arrive. 他是倒数第二个到的。8. cant help but 不由得不You cant help but respect them. 你不由得不尊敬他们。When they gave him a ticket to the game, he couldnt help but go. 他们给了他一张看球赛的票，他不由得不去。I cant help but wonder what I should do next. 我不由得不想知道下一步该怎么办。【注意】不要按汉语意思将“虽然但是”直译为althoughbut：误：Though we are poor, but we are happy. (去掉though或but中任一个)but 与 however的用法区别两者均可表示转折或对比，意为“但是”、“可是”、“然而”等，但有区别：1. 表示转折时，but 是连词。如：He is young but very experienced. 他虽年轻，但经验很丰富。He has three daughters but no sons. 他有3 个女儿，但没有儿子。He likes sports, but his wife likes music. 他喜欢运动，而他妻子则喜欢音乐。2. however 表示“然而”、“可是”时，有的词书认为它是连词，有的词书认为它是副词。之所以将其视为副词，也许是因为像许多副词一样不仅能位于句首，而且能位于句中(注意前后使用逗号)，甚至句末 (注意其前也用逗号)。如：Later, however, he changed his mind. 可是他后来改变了主意。He hasnt arrived. He may, however, come later. 他还没有到，不过他等会儿可能会来。He said that it was so; he was mistaken, however. 他说情况如此，可是他错了。注意：以上各例中的 however 不能换成 but，但可用 but 来改写。如：He said that it was so, but he was mistaken. 他说情况如此，可他错了。3. 当连接两个句子时，其前通常应用分号，或另起新句。如：Its raining hard; however, I think we should go out. / Its raining hard. However, I think we should go out. 雨下得很大，但我想我们还得出去。注意：上例中的 however 不能换成 but，但可用 but 来改写 (注意所用标点的变化)。如：Its raining hard, but I think we should go out.yet的用法1、yet用作连词时，与but一样也主要用于转折，意为“但是”“而”：I have failed, yet I shall try again. 我失败了，但我还要尝试。The judge was stern, yet completely fair. 法官很严峻，却完全公正。They are the same, yet not the same. 它们又一样，又不一样。It is strange, yet it is true. 那真是怪事，然而却是事实。Ive been away only for three years, yet I can hardly recognize my hometown. 我仅在外三年，可我几乎认不出我自己的故乡了。He said he was our friend, yet he wouldnt help us. 他说他是我们的朋友，但却不肯帮助我们。2、有时用在句首。如：Yet the house was cheerful. 但屋子里显得很欢快。Yet its population has doubled. 但它的人口翻了一番。3、yet有时可与并列连词and或but连用，构成习语and yet和but yet，意为“虽然如此”“可是”“然而”，与单独使用的yet意思相同。如：Hes not really nice-looking, and yet he has enormous charm. 他并不十分好看，可是他很有魅力。Shes a funny girl, but yet you cant help liking her. 她是一个奇怪的姑娘，但你禁不住会喜欢她。I gave him ten pounds (and) yet he was not satisfied. 我给了他十镑但他仍不满足。Shes vain and foolish, and yet people like her. 她很虚荣愚蠢，但人们却喜欢她。She drove very fast to the airport, but yet, and yet, but yet she missed the plane. 她开快车去机场，可还是误了飞机。4、根据英语习惯，although不能与连词but搭配使用，但是although可以与yet搭配连用（此时的yet可视为副词）。如：Although we are poor, yet we are happy. 尽管我们穷，但我们很快活。Although we have made some progress, yet we still have a long way to go. 我们虽然取得了些进步，但还是远远不够的。连词while考点知识归纳while是大家比较熟悉的一个词，但是许多人对它的了解是不全面的，你可能只知道它表示“当的时候”，甚至可能还知道它与when, as的用法区别。但是，非常遗憾，你所知道的这些东西都是有关while用法的“基础知识”，却不是一般英语考试的“考点知识”。请看下面两道考题：1、考查表示时间的用法，其意为“当的时候”。如：We must strike while the iron is hot. 我们要趁热打铁。 Stand still while I take your photograph. 我给你拍照时站着不要动。Have we got enough books to read while we are on holiday? 假期里我们有足够的书看吗?Were there any calls for me while I was out? 我出去的时候，有人来过电话吗? She hates anyone listening while she is telephoning. 她打电话时不愿让任何人听。2、考查表示让步的用法，其意为“尽管”“虽然”。如：While the work was difficult, it was interesting. 虽然工作有难度，但很有趣。 While I understand what you say, I cant agree with you. 虽然我理解你的意思，但我还是不同意。While the Internet is of great help, I dont think its a good idea to spend too much time on it. 虽然因特网很有帮助，但我还是认为在其上花太多的时间不是个好主意。While we dont agree we continue to be friends. 尽管我们意见不同，我们还是朋友。While I did well in class, I was a poor performer at games. 虽说我学习不错，我运动却不行。While a few became richer, many did not. 虽然一些人变得更富有了，但多数人并非如此。3、考查表示对比的用法，其意为“而”“但”。如：In some places women are expected to earn money while men work at home and raise their children. 有些地方妇女挣钱，而男子则在家里持家和带孩子。I went swimming while the others played tennis. 我去游泳，而其余的人则去打网球了。Air is a fluid but not a liquid, while water is both a fluid and a liquid. 空气是流体不是液体，水是流体也是液体。Some people waste food while others havent enough. 一些人糟踏食物而另一些人却食不果腹。Some people waste food while others havent enough. 一些人糟踏食物而另一些人却食不果腹。I went swimming while the others played tennis. 我去游泳，而其余的人则去打网球了。Prices are rising sharply, while incomes are lagging far behind. 物价飞涨而收入却远远落后。注意：这样用时，while引出的句子通常位于末，但有时也可位于句首。如：While most children learn to read easily, some need extra help. 大多数儿童学会阅读很容易，有一些儿童却需要特别帮助。While some languages have 30 or more different vowel sounds, others have five or less. 有些语言有30个或更多的元音，而其他语言只有5个或更少的元音。While Deauville is a holiday resort, Trouville is more of a working town. 特维尔是个度假胜地，而特鲁维尔更多的却是个工业城市。4、考查其省略用法，即主句与从句主语相同，且从句谓语动词含有动词be时，通常可省略从句主语和动词be。如：While (he was) in prison, she wrote her first novel. 她在狱中写出了第一部小说。 He had strayed from home while still a boy. 他小时候就离开家到处流浪了。 He fell asleep while (he was) doing his homework. 他做着做着功课就睡着了。I was only listening to the radio with half an ear, while (I was) preparing some food. 我正在做吃的东西，没太留心听收音机。(二)、表选择的并列连词主要 or (或者，还是，否则), eitheror(不是就是), neitheror(既不也不), otherwise (要不然)等。如：Be careful about what you say or you may regret it. 当心你讲的话，否则你会后悔的。Either say youre sorry or else get out! 你要么道歉，要么滚开!Neither does he smoke nor does he drink. 他既不抽烟也不喝酒。Seize the chance, otherwise you will regret it. 要抓住机会，否则你会后悔的。注：neithernor连接两个句子，注意用倒装语序。or的用法归纳 1、表示选择，意为“或”“还是”：Is the radio off or on? 无线电关上了还是开着的?Would you prefer tea or coffee? 你喜欢茶还是咖啡？Is he asleep or awake? 他睡着了还是醒着?Are you going to America by boat or by air? 你到美国是坐船还是坐飞机？You may go or stay, according as you decide. 是去是留由你自己决定。Are you from North China or South China? 你是华北人还是华南人?2、表示一种否定的条件，意为“否则”：Come on, or well be late. 快点，否则我们要迟到了。Hurry up, or youll be late for school. 赶快，否则你上学就要迟到了。Dress warmly, or else youll catch cold. 穿暖和点，否则你会感冒的。Be careful, or youll break that vase! 小心，否则你会把那花瓶打碎!Cross the road very carefully. Look both ways, or you might be knocked down. 过马路要非常小心，要看两边，不然会被车撞倒。 3、可表示“要不就是”：He must be joking, or else hes mad. 他一定在说笑话，要不就是疯了。The book must be here, or else youve lost it. 这书一定在这儿，要不就是你丢失了。 4、用于否定句中代替and。He was not clever or good-looking. 他不聪明，也长得不好看。比较：They sang and danced. 他们既唱歌又跳舞。They didnt sing or dance. 他们既没有唱歌也没有跳舞。 5、用于习语(from )The work is more or less finished. 工作大体上完成了。They consist of 1700 or more tribes. 他们由1700个或更多部族构成。Theres just one or two details I want to make sure about. 还有一两个细节我想弄清楚。Either your mother or your father may come with you. 你母亲或是你父亲会陪你去。(三)、表示因果关系的并列连词。主要有 for(因为), so(因此)等。如： He shook his head, for he thought differently. 他摇了摇头，因为他有不同想法。He told me to do it, so I did it. 他让我这样做，于是我就这样做了。The child had a bad cough, so his mother took him to the doctor. 这孩子咳得很利害，所以他妈妈带他去看医生。You are supposed to get rid of carelessness, for it often leads to serious errors. 你们一定要克服粗枝大叶，因为粗枝大叶常常引起严重的错误。注意：for表示结果通常不能放句首，也不能单独使用。连词for的用法 1、for用作连词，主要表示理由，用于引起的分句对前面的话进行解释，常用逗号把它和前面的分句分开。如：She was angry, for she didnt know French. 她生气了，因为她不懂法语。He must be out, for there is no light in the room. 他准是出去了，因为屋里没有灯。He shook his head, for he thought differently. 他摇了摇头，因为他有不同想法。The days were short, for it was now December. 白天很短，因为这时已经是十二月。We rarely stay in hotels, for we cant afford it. 我们很少住旅馆，因为我们住不起。You neednt have watered the flowers, for it is going to rain. 你本不必浇那些花，因为就要下雨了。He took the food eagerly, for he has eaten nothing since dawn. 他狼吞虎咽地吃了起来，因为他从天亮就没吃过东西。He was busy packing, for he was leaving that night. 他那时正忙着打点行李，因为那天晚上他就要走了。She does not go out in the winter, for she feels the cold a great deal. 她冬天不出门，因为他特别怕冷。 2、for表示结果通常不能放句首，也不能单独使用。for表示原因时的四个“不能” 1、for引导的从句不能位于它所解释的动词之前：Because it was wet he took a taxi. 因为下雨，他叫了一辆出租车。（这里不能用for）2、for引导的从句不能位于not, but或任何连词之后：He stole, not because he wanted the money but because he liked stealing. 他偷东西，并不是因为他想要钱，而是他有这种毛病。（这里不能用for） 3、for引导的从句不能用于回答问题：Why did you do it? 你为什么这么做? I did it because l was angry. 因为我生气才这么做的。（这里不能用for） 4、for引导的从句不能单单用来复述已讲过的话，而必须包括新的内容：He spoke in French. She was angry because he had spoken in French. 他讲法语。因为他讲法语，她生气了。（这里不能用for）但是说：She was angry, for she didnt know French. 她生气了，因为她不懂法语。（这里用for是正确的，也可用because）注意：之所以有这些用法上的限定，其理由是for引导的从句不能直接说明某一特定动作发生的原因，而只能提供一些起帮助解释作用的附加说明。例如：The days were short, for it was now December. 天短了，现在已是12月了。He took the food eagerly, for he has eaten nothing since dawn. 他狼吞虎咽地吃了起来，因为他从天亮就没吃过东西。When I saw her in the river I was frightened. For at that point the currents were dangerous. 我看见她在河里时，吓坏了。那个地方水流非常危险。注意：在口语中，for从句前常稍停一下。在笔语中，在此处常有一个逗号。有时也用一个句号断开，如最后一个例子所示。上面三个例句中也可用becatse, 但用for更好些。连词so的用法1、so用作连词，主要用于表结果，意为“所以”：Its very cold, so wear a heavy coat. 外边很冷，因此穿一件厚大衣。The door was locked, so we couldnt get in. 门上锁了，所以我们进不去。I couldnt have won, so I didnt go in for the race. 我不可能获胜，因此我没参赛。The play began at eight, so they must dine at seven. 戏八点开始，因此他们必须七点吃饭。It was dark, so I couldnt see what was happening. 天很黑，所以我看不见发生了什么事。There happened to be a policeman on the corner, so I asked him the way. 恰好拐角处有一位警察，我就向他问路了。2、有时可与并列连词and连用，构成习语and so(相当so)：He told me to do it and so I did it. 他叫我那么做，所以我就做了。He worked hard and so he succeeded. 他勤奋工作，所以他取得了成功。There was so much to eat and so few people to eat it. 有这么多东西可吃，而吃的人又这么少。I forgot to post the letter, and so she never heard about my divorce. 我忘了寄那封信了，所以她一直不知道我离婚的事。3、不要按汉语意思将“因为所以”直译为becauseso：误：Because he was ill, so he couldnt come.(去掉because或so中任意一个)(四)、表示并列关系的并列连词。这类连词主要有 and , or , eitheror , neithernor , not onlybut (also) , bothand , as well as ，when(=and just at this time 就在这时)等。如：Give him an inch and he will take a mile. 他会得寸进尺。Not only did he speak more correctly, but he spoke more easily. 不仅他讲得更正确，也讲得更不费劲了。He was about to go to bed when the telephone rang. 他正要上床睡觉，这时电话铃响了起来。He didnt go and she didnt go either. 他没去，她也没去。The weather is mild today; it is neither hot nor cold. 今天天气很温暖，不冷也不热。Both New York and London have traffic problems. 纽约和伦敦都存在交通问题。It is important for you as well as for me. 这对你和对我都很重要。People who are either under age or over age may not join the army. 年龄不到或者超龄的人都不得参军。连词and 用法方方面面1. 基本义为“和”“又”“而且”等，但它有时还可表示对比或转折，相当于汉语的“而”“但”“却”。如：Shes a bank manager and Im just a road-sweeper. 她是银行经理，而我不过是个扫街的。Ive read Tonys book and I dont understand it. 我读过托尼的书，但我不懂。He hasnt had anything published and he calls himself a writer! 他什么都没发表过，却自称作家！2. 有时用于连接两个相同的词语，主要有以下用法：(1) 连接两个相同的比较级，表示“越来越”。如：The weather is getting colder and colder. 天气越来越冷了。Your English is getting better and better. 你的英语越来越好了。Computers are becoming more and more complicated. 计算机变得越来越复杂。(2) 连接两个相同的动词，表示动作的反复或连续。如：He coughed and coughed. 他咳个不停。He tried and tried but without success. 他试了又试却未成功。(3) 连接两个相同的副词，也表示动作的反复或连续。如：He kept moaning on and on. 他呻吟不已。(4) 连接两个相同的名词，有以下两种主要用法：表示“许多”。如：They talked for hours and hours. 他们谈了很长很长时间。The road went on for miles and miles. 这条路很长很长。强调差别，意为“与不同”。如：Dont worry there are rules and rules. 别担心规则跟规则不一样。I like city life but there are cities and cities. 我喜欢城市生活，但城市之间也有差别。3. 在come和go以动词原形出现时，其后习惯上不跟不定式表示目的，而是用“and+动词原形”表示目的。如： I must go and help my mother. 我必须去帮助我母亲。Ill come and check the accounts. 我将来清理账目。Go and buy yourself a new pair of shoes. 去给自己买双新鞋吧。Come and play a game of bridge with us. 来跟我们一起打桥牌吧。注意：但是，如果go和come不是以动词原形出现，而是以过去式、过去分词、现在分词、动名词等方式出现，则其后应不定式表示目的。如：Ive come to collect my book. 我来取我的书。I m thinking of going to look for mushrooms. 我想去采蘑菇。I didnt come to talk to Bill; I came to talk to you. 我不是来跟比尔说话的，我是来跟你说话的。I went to buy a newspaper and lost my place in the queue. 我去买了份报纸，回来就找不到我排队中的位置了。另外，在come, go 之后的 and 有时可以省略（尤其在美国英语中）。如：Ill come (and) see you later. 我晚些时候再来看你。4. 用在祈使句后，表示结果，意为“那么”（暗示一种条件）。如：Work hard and youll pass the examinations (=If you work hard, youll pass the examinations). 努力吧，你考试会及格的。Arrive late once more and youre fired (=If you arrive late once more, youre fired). 再迟到一次，就把你开除。有时也可以不是用于祈使句后表示结果。如：One more step and I will fire. 你再动一步，我就要开枪了。5. 用在 good, nice, fine 等之后，表示“很”“挺”。如：I wont go until Im good and ready. 我完全准备好了才去。Make sure you cut the bread nice and thick. 你一定要把面包片切得厚厚的。6. 在主从复合句中，不要在主句前误加 and。如：使用两个镜子能看见自己的头的后部。误：If you use mirrors, and you can see the back of your head.正：If you use mirrors, you can see the back of your head.7. 某些用 and 连接的两个词，与汉语顺序相反，不要按汉语词序颠倒过来。如：rich and poor 贫富 land and water 水陆right and left左右 north and south 南北food and drink 饮食 food and clothing 衣食8. 比较以下各组句子有无连词 and 的差别：天气晴朗，我们出去散了步。正：The weather being fine, we went out for a walk.正：The weather was fine, and we went out for a walk.教室里包括老师有5个人。正：In the classroom there are five people, the teacher included.正：In the classroom there are five people, and the teacher was included.他有两个小孩，都很顽皮。正：He has two children,both of whom are naughty.正：He has two children, and both of them are naughty.三、从属连词的用法(一)、引导时间状语从句的从属连词1、表示“当时候”或“每当”的时间连词。主要的 when, while, as, whenever。如：Dont talk while youre eating. 吃饭时不要说话。Vegetables are best when they are fresh. 蔬菜新鲜时最好吃。He came just as I was leaving. 我正要走时他来了。2、 表示“在之前(或之后)”的时间连词。主要的有before, after。如：Try to finish your work before you leave. 离开前设法把工作做完。After we have finished tea, we will sit on the grass. 喝完茶之后我们将坐在草地上。3、表示“自从”或“直到”的时间连词。主要的有since, until, till。如：Shes been playing tennis since she was eight. 她从八岁起就打网球了。Hold on until I fetch help. 坚持一下，等我找人来帮忙。Never trouble trouble till trouble troubles you. (谚)不要无事惹事。带有until状语从句的主句谓语有何特点请看看这道题：We _ until he came. A. stoppedB. arrivedC. leftD. waited此题应选D。选项A，B，C都有可能被误选。要弄清此题需弄清以下几点：1. until 意为“一直到”，其相应主句的谓语只能是持续性的，而不能是终止性的。它表示的是：主句动作一直持续到从句动作发生时为止。以上一题的A，B，C选项是错的，主要是因为其含义荒唐：若选A，句意为：我们一直在停止，直到他来就不停止了。若选B，句意为：我们一直在到达，直到他来就不到达了。若选C，句意为：我们一直在离开，直到他来就不离开了。以上各句的意思显然不通。选D是对的，因为其意为：我们一直在等，直到他来就不等了(即我们一直等到他来)。2. 上面说到，与 until 从句连用的主句谓语不能是终止性动词，但是若这个谓语是否定的，则可以是终止性动词，因为终止性动词一旦被否定，即成为状态，而状态都是可以持续的(注：not.until.意为：直到才)：误：We stopped until he came. 正：We didnt stop until he came. 直到他来我们才 停止。误：We started until the rain stopped. 正：We didnt start until the rain stopped. 直到 雨停我们才开始。误：He finished it until it was dark. 正：He didnt finish it until it was dark. 直到 天黑他才完成。3、 表示“一就”的时间连词。主要的有as soon as, the moment, the minute, the second, the instant, immediately, directly, instantly, once, no soonerthan, hardlywhen等。如：Ill let you know as soon as I hear from her. 我一接她的信就通知你。The moment I have finished Ill give you a call. 我一干完就给你打电话。I came immediately I heard the news. 我一听到这个消息，马上就来了。Once you begin you must continue. 你一旦开始, 便不可停下来。4、 表示“上次”、“下次”、“每次”等的时间连词。主要的有every time(每次)，each time(每次)，(the) next time(下次)，any time(随时)，(the) last time(上次)，the first time(第一次)。如：Ill tell him about it (the) next time I see him. 我下一次见到他时，我就把这个情况告诉他。We lose a few skin cells every time we wash our hands. 每当我们洗手的时候，我们都要损失一些皮肤细胞。You can call me any time you want to. 你随时都可以给我打电话。注意：every time, each time, any time前不用冠词，(the) next time, (the) last time中的冠词可以省略，而the first time中的冠词通常不能省略。as 用作连词有哪些用法as 用作连词用法如下：1、表示伴随，意为“随着”。如：As time passed, things seemed to get worse. 随着时间的推移，情况似乎变得更糟了。若其后不接从句，而接名词，则用介词 with 表示“随着”。如：With the development of modern agriculture and industry, more and more waste is produced. 随着现代工农业的发展，污染越来越严重了。2、表示让步，意为“虽然”“尽管”，要用于倒装句（相当于 though，但语气稍弱）。如：Boy as he was, he behaved like a girl. 他虽然是个男孩，但举止却像个女孩。Much as I like you, I couldnt live with you. 我尽管很喜欢你，却不能和你一起生活。Try as he would might，he couldnt open the door. 他试过多次了，却仍打不开门。3、表示时间，意为“当时候”。如：He dropped the glass as he stood up. 他站起来时，把杯子摔了。As I was coming here, I met your brother. 我来这里时碰到了你的弟弟。注意，as 引导时态状语从句时，其谓语动词通常只能是动作动词，而不能是静态或状态动词。如：她出生后不久父母双亡，是由姑母抚养大的。误：Her parents died as she was a baby and she was brought up by her aunt.正：Her parents died when she was a baby and she was brought up by her aunt.4、表示原因，引导原因状语从句时，其谓语动词可以是动作动词，也可以是状态动词。如：As you werent there I left a message. 因为你不在那里，我留了个信儿。另外，引导原因状语从句，可用以下这样的倒装语序。如：Tired as she was, I decided not to disturb her. 因为她累了，我就决定不打扰她了。Writing hurriedly as she was, she didnt notice the spelling errors. 因为写得仓促，她没有注意其中的拼写错误。(二)、引导条件状语从句的从属连词。这类连词主要有if, unless, as so long as, in case 等。如：Do you mind if I open the window?我开窗你不介意吧?Dont come unless I telephone. 除非我打电话，否则你别来。As long as youre happy，it doesnt matter what you do. 只要你高兴，你做什么都没关系。In case it rains they will stay at home. 万一下雨，他们就呆在家里。注意：在条件状语从句中，通常要用一般现在时表示将来意义，而不能直接使用将来时态。不过，有时表示条件的 if之后可能用 will，但那不是将来时态, 而是表示意愿或委婉的请求(will为情态动词)。如：If you will sit down for a few moments, Ill tell the manager youre here. 请稍坐, 我这就通知经理说您来了。if与whether的用法区别两者在表示“是否”时的用法区别如下：1. 互换的场合引导宾语从句表示“是否”时, 两者常可互换。如：He asked if whether we wanted a drink. 他问我们是否想喝一杯。He didnt tell me if whether he would come. 他没有告诉我他是否会来。注：若是引导条件状语从句，则只能用 if (意为“如果”)。2. 通常用 if 的场合当引导一个否定的宾语从句时，通常用 if 而不用 whether。如：I dont care if it doesnt rain. 我不在乎天是否下雨。注：在个别词语 (如 wonder, not sure 等)后的从句否定式有时也可能用 whether 来引导。如：I wonder if whether he isnt mistaken. 我想知道他是否错了。3. 通常用 whether 的场合(1) 引导主语从句且放在句首时。如：Whether he will come is still a question. 他是否会来还是个问题。注：若在句首使用形式主语 it，而将主语从句放在句末，则有时也可用 if 来引导。如：It was not known whether if he would come. 不知他是否会来。(2) 引导表语从句时。如：Th