一、时间状语从句 二、地点状语从句 三、方式状语从句 四、程度状语从句
六、结果状语从句 七、目的状语从句 八、条件状语从句 九、让步状语从
1．时间状语从句通常用下列从属连词来引导：after, before, as,
once, till, until, (ever) since, when, whenever, while, now (that), as long as, as soon as。如： Now (that) you’ve grown up, you must stop this childish behaviour. Whenever we met with difficulties, they came to help us. Come and see us whenever you have time. People do not know the value of health till they lose it.
2．有些词，如 immediately, directly, instantly等，当用于 as soon as 意义时，也可以引导时间状语从句，如： I got in touch with him immediately I received his letter. My sister came directly she got my message. The machine will start instantly you press the button. I’ll telephone you directly I hear the news. Will you look for it immediately you get there?
3．某些表示时间的名词词组，如 the (very) moment (= as soon as ), the minute (= as soon as ), the instant (= as soon as ), the day, the
year, the morning, every time, each time, next time, the first time等，
I’ll tell you about it the moment you come. I started the instant I heard the report.
The instant she saw him she knew he was her brother.
Every time I catch a cold, I have pain in my back. I’m going to see him next time he comes to Shenzhen.
He left Europe the year World War Ⅱbroke out.
He had impressed me that way the first time I met him. I started the very moment I got your letter. I’ll tell him the minute (that) he gets here.
? 4．有些关联从属连词，如 no sooner … than / hardly … when / scarcely … when / barely …when 等， 也能引导时间状语从句。 ? △ 如果把no sooner, hardly, scarcely, barely置于句首， 它所连带的这部分就要倒装，如： ? She had no sooner heard the news than she fainted. ? No sooner had she heard the news than she fainted. ? They had hardly started to work when the trouble began. ? Hardly had they started to work when the trouble began. ? He had scarcely entered the room when the phone rang. ? Scarcely had he entered the room when the phone rang.
1．方式状语从句通常由 as, as if, as though 来引导，如： You must do the exercises as I show you. Please do exactly as your doctor says. It looks as if it might snow / is going to snow. He acted as / though nothing had happened. He walked as if he was / were drunk. Mary was behaving as though she hadn’t grown up.
2．在非正式文体或口语中，也可用 the way (that) (= as = in the way in which), how, like等来引导，如： Jean doesn’t do it the way I do. She is doing her work the way I like it done. You can do the job how you like. The landlord was watching him like (= just as) a cat watches a mouse. Do you make bread like you make cakes?
程度状语从句可用 to such an extent that… / to such a degree that… 来引导，如： The temperature rose to such an extent that the
firemen had to leave the burning building.
The temperature lowered to such a degree that the water froze. 试比较： The temperature rose so high that the firemen had to leave the burning building. The temperature lowered so much that the water froze. 从以上例句可以看出，程度状语从句往往也表示达到某种程度 时所引出的结果，所以程度状语从句和结果状语从句在意义上有相 通之处。
1．引导原因状语从句最常用的连词是 because, since, 和as，
所引导的从句可以放在主句之前，也可放在主句之后。其 中 because语势最强，since次之，as又次之。
△ because通常表示说话人认为这种理由或原因是听话人所不知道 的，全句强调的重点在原因上，不在主句表示的结果上。回答why
句，不能用since, as等，如： Because I can’t see very well, I have to sit near the front.
It was because he was ill that he didn’t go with us.
It is because he was ill that he didn’t come.
△ since 和as 引导的句子，重点在主句的内容，其原因或理由在说
话人看来已很明显，或已为听话人所熟悉，since 和as 只是一种附 带的说明原因，不是对原因进行强调，如： As he is working hard, he is likely to succeed. Since he can’t answer the question, you’d better ask someone else. As / Since he was not at home, I spoke to his brother. Since you insist, I will reconsider the matter. As he was in a hurry, he left his bag at home.
△ for 是并列连词，它引导的句子只能后置。表示因果关系时， 可以和because 换用；但当它用于对主句的内容加以解释或推断时， 不能用because 代替，如： He couldn’t have seen me, because / for I was not here. The ground is wet, for / because it rained last night. It rained last night, for the ground is wet this morning. △ because 之前可以加上simply, only, just 等强调词，如： You shouldn’t get angry just because some people speak ill of you.
2．复合连词也可以引导原因状语从句，这些连词有：now (that), seeing (that), considering (that), for the reason that, by reason that, for fear that, that等，如：
Now (that) (= Since) you mention it, I do remember. Now (that) he is absent, you’ll have to do the work by yourself. Now (=Since) the rain has stopped, let’s start. Seeing (that) all the guests have arrived, let’s have dinner. Considering that they are just beginners, they are doing quite a good job. She didn’t go for fear that she would get lost. He has done very well, considering (that) he has no experience. I haven’t finished writing the report yet, not that (= not because) I dislike the work, but that (= but because) I have not time.
? 3．在“主语+ be + 形容词+ that ”句型中，主语 通常是人，形容词通常为：glad, happy, pleased, sorry 等表示感情的形容词，这时that 可以看作 原因状语从句，如： ? We are glad that (= because) we have reaped another bumper harvest. ? I’m glad (that) you are all right. ? We are sure that our team will win. ? I’m pleased that you have decided to come.
结果状语从句往往放在主句之后，通常主句是因，从句是果，这 和原因状语从句刚好相反，如： He was ill, so that he didn’t come. He didn’t come because he was ill. 1．结果状语从句通常用下列连词引导：so …that, such (a) …that, such that, so that, that 等，如： He was so angry that he left the room without saying a word. The book is written in such simple English that we beginners can understand it without much difficulty. It was such a bad accident that several people got injured. His diligence was such that he made great progress. He didn’t plan his time well, so that he didn’t finish the work in time. She worried so that she could hardly eat her supper. What have I done that you should be so angry with me?
2．应注意的几个问题： ① 在非正式文体中，由 so…that, such (a)…that引导的结果状语从 句，往往可以省略连词 that，这时，从句之前往往用逗号与主句隔 开，在口语中则用停顿表示省略。 He was so tired (,) (that) he could hardly stand. Peter is such a good boy (,) (that) he is loved by everybody. You walk so fast (that) I can’t keep pace with you. We left in such a hurry (that) we forgot to lock the door. He was so rude (that) she refused to speak to him. ② 当so 修饰动词时，后面应稍停顿，如： His heart beat soΔthat he could hardly breathe. She worried so Δthat she could hardly eat her supper. ③ 当so位于句首时，主句的语序应倒装，如： So badly was he injured that he had to go to the hospital. So small was the mark that I could hardly see it.
1．目的状语从句通常使用的连词有：so that, in order that, that, so。 否定的句式常用 lest, in case, for fear that来引导。 △ 目的状语从句中一般要有 can, may, could, might, will, would, should等情态动词，如： Bring it closer (so) that I may see it better. I put down his address for fear that I should forget it. The teacher must speak clearly so that his students can / may understand well. We’ll sit nearer the front so we can hear better. (非正式或口语) The driver looked over the engine carefully lest it (should) go wrong on the way. Please remind me of it again tomorrow in case I forget. Take an umbrella with you, in case (= for fear) it rains / it may rain / it should rain. He left early in case he should miss the train.
1．条件状语从句通常用下列连词引导：if, unless, supposing (that) （仅在问句中使用），suppose (that), in case, so / as long as, so far as, on condition (that), provided (that), 等，如： In case he comes, let me know. You can go out, as / so long as you promise to be back before eleven. I will come again tomorrow provided (that) I have time. (= if) Supposing (that) it rains tomorrow, what shall we do? (= if) Unless you tell him yourself, he’ll lose faith in you completely. We’ll let you use the room on condition that / provided that you keep it clean and tidy.
2．so that / so既可以引导目的状语从句，又可以引导结果 状语从句，其区别可以根据上下文的意义来判断，也可以 从其结构上来判断。
① 凡在讲话时，so that / so从句之前有停顿，在文字中so that / so 从句之前有逗号，则为结果状语从句，否则为目的状语从句，如： We all arrived at eight, so (that) the meeting began promptly. (结 果状语从句) We’ll come at eight so (that) the meeting can begin early. (目的状 语从句)
? ②有时，由 so that或 so 引导的结果状语从句之前并没 有逗号，这时，就要看从句中有没有 can, may, could, might, will, would, should等情态动词，如果有，多半是 目的状语从句，如果没有，多半是结果状语从句，如： ? I am going to the lecture early so that I’ll get a good seat. (目的状语从句) ? I went to the lecture early so that I got a good seat. (结果状语从句) ? ③ 目的状语从句可以移至句首，而结果状语从句不能 前移，如： ? So that he could be heard in every room, John spoke through a microphone. (目的状语从句) ? John spoke through a microphone so that he was heard in every room. (结果状语从句)
2．有时可以把祈使句作为条件从句，祈使句后面要搭配and，如： Come tomorrow, and I will tell you. (= If you come tomorrow, …) Persevere and you will succeed. Give him an inch and he’ll take a mile. (= If you give him an inch, he’ll …)
注：当表示否定的条件时，可用连词or 或otherwise， 如： Hurry up, or (else) you’ll be late. Make up your mind, or you’ll miss the chance. Start at once, or / otherwise you’ll miss the train. (= If you don’t start at once, …) (= Unless you start at once, you’ll miss the train.)
3．if only是if的强调式，通常表示说话人的愿望，如： If only it clears up, we’ll go. If only somebody had told us, we could have warned you. 注：if only 引导的状语从句有时可以不依附于主句而独立存在， 表示说话人的希望、愿望或遗憾等心情，如： If only he comes in time. (I hope he will come in time.) If only he didn’t drive so fast. (I wish he didn’t drive so fast.) If only I hadn’t been late for work. (I wish I hadn’t been late for work.)
4．在真实条件句中，从句动词通常用一般现在时表示将来时间， 主句通常带有情态动词，如： If you move, I’ll shoot you. If I press this button, what will happen? If you come, you can see it. If you finish early, you may go. 注① 当从句表示将来已经完成或正在进行的动作时，动词用现在 完成时或现在进行时，如： I will return the book on Monday if I have read it. The police won’t take your car away if you are sitting in it. 注② 如果从句表示现在的意图、意愿、决心等，则可以用will / shall，如： If you will read the book, I’ll let you have it. If you will help me, we can finish by six. If you will give up smoking / drinking, your health will improve.
If he should hear of your marriage, he would be surprised. If you should hear the news, please let us know. If you should be interested, I’ll tell you the whole story. If it should rain, we had better stay indoors. If he should come tomorrow, I would tell him everything. 注：在正式文体中，可用 should I (we, you etc) 代替 If I (we, you
“should + 不定式”，主句动词可根据意义需要采取不同形式，如：
etc) should …，如：
Should I be free tomorrow, I will come. Should you see Mike, will you ask him to ring me up?
Should you see my mother, tell her I am quite well.
① 当从句表示与现在事实相反的条件时，从句动词用一般过去时 或 were型虚拟式，主句动词用 would / should / could / might + 不定 式，如： If I were you, I should consult a doctor. If I lived in the twenty-first century, my life might be different in a number of ways. ② 当从句表示与过去事实相反的条件时，从句动词用过去完成时， 主句动词用would / should / could / might +不定式完成式，如： If he had tried hard last term, he would have succeeded. If he had taken his doctor’s advice, he might not have died.
③ 当从句表示将来不大可能实现的条件时，从句动词用一般过去 时或 were / was to +不定式，主句动词用would / should / could / might +不定式，如： What would you do if it snowed tomorrow? He wouldn’t do it unless you were to order him to. ④ 在正式文体中可用“were +主语”等倒装结构代替“if +主语+ were”等结构；“had +主语 + ed分词”代替“if +主语+ had + ed分 词”结构，如： Were I in your place, I would be very worried. Were John to go to the university, he would have to work hard. Had the captain been more careful, his ship would not have been sunk. Had it not been for the expense, I should have gone to Italy.
? ③ 当从句表示将来不大可能实现的条件时，从句动词 用一般过去时或 were / was to +不定式，主句动词用 would / should / could / might +不定式，如： ? What would you do if it snowed tomorrow? ? He wouldn’t do it unless you were to order him to. ? ④ 在正式文体中可用“were +主语”等倒装结构代替 “if +主语+ were”等结构；“had +主语 + ed分词”代 替“if +主语+ had + ed分词”结构，如： ? Were I in your place, I would be very worried. ? Were John to go to the university, he would have to work hard. ? Had the captain been more careful, his ship would not have been sunk. ? Had it not been for the expense, I should have gone to Italy.
7．unless 与if … not 的用法比较： If you don’t start at once, you will miss the train. Unless you start at once, you will miss the train. unless 在意义上相当于if … not ，在有些场合两者可以交替使用， 但在有些场合又不可以互换，以下是不可互换的情况：
① 当if … not 引导非真实条件状语从句时，一般不可以改用unless， 如： If she weren’t so silly, she would understand. (事实上她很傻，改 成Unless she were so silly…含义为她不傻) If I hadn’t stopped her, she would have jumped into the river. (事 实上我阻止了她，改成Unless I had stopped her…含义为我没有阻 止她。)
② unless 表示除外的唯一条件，因此通常不能用and 连接两个 unless 从句，而if … not 则不受此限，如： She won’t lose weight if she does not keep a diet and if she does not take exercises every day. She won’t lose weight unless she keeps a diet and takes exercises every day. (不说：unless she keeps a diet and unless she takes exercises every day.)
③ unless 从句中可用否定词，而 if … not 从句中不可再加否定词， 因此在 unless 引导的否定从句中，不可用 if … not 代替 unless ，如： I will go unless no one else does. I will go if no one else doesn’t. × Don’t ask me to explain unless you really don’t understand. Don’t ask me to explain if you really not don’t understand. × ④ 在if … not 从句中通常用非肯定词，而在 unless 引导的肯定形式 的条件从句中，通常用肯定词，而不用非肯定词，如： I will be very angry if you haven’t spoken to her yet. I will be very angry unless you have already spoken to her.
比较状语从句一般由从属连词as或than来引导，这种从句常采 用省略句的句型，如： He worked as fast as a skilled worker. The project was completed earlier than we had expected. He is as young as you (are young). Please come as soon as (it is) possible. 区别：We know you better than he (knows you). We know you better than (we know) him.
注① 在否定句中，用as…as 或so…as 均可，但后者语气更强调， 如： He is not as / so young as you.
注② the…the… 句型也是比较状语从句的一种，例如： The harder we work, the better we shall serve the people. 其中the 为连接副词，既起连接作用，又修饰后面的副词。 注意省略： The sooner he comes, the better (it will be). The higher the ground (is), the cooler the air (will be).
十一、as far as 或so far as 可以引导状语从句，有些语法 书将其称之为“限制状语从句”，如： As far as / So far as I can see, this is a thorny problem. So far as I am concerned, I have no objection.