狀語從句在句中作狀語，修飾主句中的動詞、形容詞或副詞等。狀語從句放在主句之前時，常用逗號分開；放在主句之后，一般不用逗號。狀語從句按其意義和作用可分為時間、原因、條件、、讓步、地點、目的、結果、方式、比較等九種。
1．時間狀語從句
時間狀語從句通常由when, while, as, before, after, (ever) since, till, until, as soon as等從屬連詞引導。
When he was skating round the lake, he suddenly fell.
I haven’t heard from him since he left school.
As soon as he appeared on the stage, the audience began to cheer.
注意：時間狀語從句中用一般現在時表示將來意義。例如：
I will go on with the work when I come back tomorrow.
I will send you email as soon as I reach New York.
1）when, while, as引導時間狀語從句時的異同
when引導的時間狀語從句中的謂語動詞既可以是延續性動詞，也可以是短暫性動詞；從句的動作可以和主句的動作同時發生，也可以先于主句的動作發生，此時相當于after。當when從句謂語動詞是延續性動詞時，可與while互換。
I often missed my home a lot when I was abroad.. ( =while )
When they came home, I was cooking dinner. (不能用while)
When the film ended, people rushed out of the hall. ( =after )
when從句置于主句后面，同時從句中謂語動詞又是短暫性動詞時，常表示“此時突然……”。
I was walking along the street when I caught sight of a tailor’s shop.
He was enjoying his dinner when a loud noise came on the door.
while引導的動作必須是持續性的，強調主句和從句動作的同時發生，有時側重主句和從句動作的對比。
He took a bath while I was preparing dinner.
as常可與when, while通用，但它較強調主句和從句動作的同時發生，常譯作“邊……邊”也可用來說明兩種正在發展和變化的情況，此時常譯作“隨著”。
He sang happily as he walked along the path.
The day gets longer and longer as summer comes.
2）until, till引導的時間狀語從句
主句謂語動詞為延續性動詞時，主句和從句都用肯定句式，意為“一直到”，表示主句動作一直延續到until/till從句表示的時間才終止；主句謂語動詞為短暫性動詞時，主句用否定式，從句用肯定式，意思是“一直到才”，表示主句動作到until/till從句表示的時間才開始。
He worked until/till it was dark.
He didn’t work until/till it was dark.
until和till意義相同，通常可換用，但在強調結構、倒裝句或句首，一般用until。例如：
I didn’t know about it until/till he told me.
It was not until he told me that I knew about it.
Not until he told me did I know about it.
3）since引導的時間狀語從句和before引導的時間狀語從句
since從句中的動詞不同，其起算時間也不同。since + 瞬間動詞過去時，從該動作發生時起算；since + 延續性動詞過去時，從該動作結束時起算。試比較：
He has worked very hard since he entered the factory.
(enter為瞬間性動詞，該句意為“從他入廠以來，他工作一直非常努力。”)
We haven’t seen each other since I worked in the factory.
(work為延續性動詞，該句意為“從我不在工廠以來，我們沒見過面。”可說成
We haven’t seen each other since I stopped working in the factory.）
since常用于It’s + some time + since sb. did sth.結構。試比較：
It’s two years since he joined the army. （他參軍有兩年了。）
It’s two years since he was a soldier. （他退役有兩年了）
before有時可譯為“還沒……就”。如：
He had measured me before I could say a word. （我還沒來得及說話他就給我量好了尺寸。）
I hadn’t waited long before he came. （我還沒等多久他就來了。）
I slipped out before the lecture started. （還沒等講座開始我就溜了出去。）
before也可用于it結構，與since結構比較相似，注意它們所用時態的區別，其結構通常是
It will be + some time + before sb. does sth. 或It was + some time + before sb. did sth.. 可表示將來或過去兩個概念。常譯作“……才……”。例如：
He is leaving for Australia and it will be three years before he comes back.
(他要去澳大利亞了,三年后才會回來。)
(Duing the war he joined the army and it was three years before he came back.
（戰爭期間他參了軍，三年后才回來了。）
4）as soon as等意為“一……就”的時間狀語從句的幾種不同表達
as soon as表示“一……就”，在表述已發生的動作時，hardly…when, no sooner…than也可表示同樣的意思，但主句謂語動詞要用過去完成時，從句用過去時，還可轉換成倒裝結構。
As soon as he saw the policeman, he ran away.
= He had hardly seen the policeman when he ran away.
= Hardly had he seen the policeman when he ran away.
= He had no sooner seen the policeman than he ran away.
= No sooner had he seen the policeman than he ran away.
immediately, directly, instantly, the moment, the minute, the instant,也可引導時間狀語從句，相當于as soon as的意思，用法也與as soon as基本相同。上述句子可轉換成：
He ran away immediately/directly/instantly he saw the policeman.
He ran away the moment/the minute/the instant he saw the policeman.
5）the moment, the minute, the instant, the day, the year, the first time, last time, each/every time, next time, by the time等少數表示時間概念的短語也可引導時間狀語從句。例如：
I recognized her the minute I saw her.
Her son was born the day Hongkong returned to its motherland.
He left Europe the year World War Ⅱ broke out.
He was attracted by the beauty of the city the first time he went there.
Last time I saw her, she was writing a book.
Don’t refer to the dictionary each/every time you come upon a new word.
I will go to the seaside next time I go to Dalian.
He had finished learning advanced mathematics by the time he was 14.
2．原因狀語從句
1）原因狀語從句通常由because, since, as引導。because引導的從句可以放在主句前，也可放在主句后面，表示直接的原因或理由，著重點在從句。回答why問句、用于強調結構都用because。如：
He had to do a part-time job after work because he needed money for his marriage.
---Why didn’t he come yesterday?
---Because he had something important to do.
It was because he lost it that he found it more valuable than ever.
since和as引導的原因從句更多見于句首，表示明顯的、已知的事實，語氣比because弱，分別可譯作“既然”、“由于”，著重點在主句。
Since you have to stay at home, why don’t you do some shopping on computer?.
As the weather is fine, let’s go fishing.
for也可引導表示原因的句子，但它是個并列連詞，通常表示一種推測的原因或附加的說明，語氣最弱，一般不放在句首，前面常有逗號分隔。
It must have rained last night, for the ground is wet.
2）now that, seeing that, considering that等也可以引導表示原因的從句, 語氣相當于since，常譯作“既然”，口語中that可省去。例如：
Now (that) my watch has been sold, what’s the use of the watch chain?
Seeing (that) you’re already at the door, I suppose I must invite you inside.
3．條件狀語從句
條件句可分為真實條件句和非真實條件句，非真實條件句在虛擬語氣中有詳細表述，這里只討論真實條件句。引導條件句常用的有if, unless, as(so) long as, in case等，when, once, suppose (that) 或supposing (that)，on condition that 也可引導表示條件的從句。條件狀語從句和時間狀語從句一樣，表示將來要用一般現在時。例如：
The bell is rung if there is a fire.
We won’t let you in unless you show your pass.
You may use my bike as/so long as you return it before Friday.
In case anything important happens, please call me up.
Turn off the switch when anything goes wrong.
Once you taste the noodles, you’ll never forget their delicious flavour.
Suppose/Supposing (that) you fail again this time, what will you do?
He agreed to lend him the money on condition that he paid back three times more money in three months’ time.
4．讓步狀語從句
1）通常由though, although, even/though引導，主句中不能用but，但可用yet。如：
He didn’t light the fire though/although it was cold.
Although/though he is quite old, (yet) he still tries to learn more.
I’ll try to finish the work myself even if/though it takes me days.
3） whatever, whoever, whichever, whenever, wherever, however 引導狀語從句時，分別相當于no matter what/who/which/when/where/how引導的從句，意為“無論……”。例如：
Whatever/No matter what he said, no one believed him.
Whoever/No matter who breaks the law, he will be punished.
Whichever/No matter which job you take, you should try to do well in it.
Whenever/No matter when I need his help, he comes immediately.
Wherever/No matter where you go, never forget your motherland.
However/No matter how busy he was, he would watch TV sports news every night.
注意whatever, whoever, whichever又可引導名詞性從句，注意區別。可參閱本章第一節。
3）as引導讓步狀語從句要倒裝，其結構通常是“noun/adj/adv + as + 主語+謂語(+其它成分)，主句”，可轉換成though/although從句。
Child as he is, he knows a lot. （注意：名詞前不用冠詞）
=Although/Though he is a child, he knows a lot.
Difficult as the task was, they managed to finish it in time.
=Although/Though the task was difficult, they managed to finish it in time.
Much as I like it, I will not buy it.
=Although/Though I like it much, I will not buy it.
偶爾也可見用動詞提前的讓步狀語從句。例如：
Try as he may, he can hardly do better than she.
=Although/Though he may try, he can hardly do better than she.
4）whether…or也可引導讓步狀語從句，相當于“no matter whether…or”。
Whether you come in winter or in summer, you will find it a nice place.
=No matter whether you come in winter or in summer, you will find it a nice place.
5．地點狀語從句
1）地點狀語從句常由where和wherever引導，通常可置于主句之前或之后。。
I found the books where I left them.
Make a mark where you have any questions.
We should go where(ver) we are most needed.
Where there is a will, there is a way.
Where there is water, there is life.
2）where引導的狀語從句和where引導的定語從句常可轉換，判斷它屬于哪類從句的關鍵是看where前面有沒有被修飾的、表示地點的先行詞。試比較：
Stand where you are! （狀語從句）
Stand at the place where you are! （定語從句）
Bamboo grows best where it’s wet and rainy. （狀語從句）
Bamboo grows best in places where it’s wet and rainy. （定語從句）
6．目的狀語從句
1）目的狀語從句通常由 (so) that, in order that引導,在口語或非正式文體中，有時也會用that或so引導。in order that 引導的目的從句可以放在主句后面，也可放在主句前面，而so that引導的從句通常放在主句后面。目的狀語從句中的謂語常含有may(might), can(could), should, will等情態動詞。例如：
He always takes a seat in the first row so that/in order that he can hear better.
（也可說成He always takes a seat in the first row so/that he can hear better.但用的較少。）
=In order that he can hear better, he always taked a seat in the first row.
The actress wore ordinary clothes in order that/so that she might not be recognized easily.
=In order that she might not be recognized easily, the actress wore ordinary clothes.
2）in case, for fear that, lest 等也可以引導目的狀語從句，表示 “以防…、以免…” 。如：
He left early in case he should miss the train.
Take your raincoat in case it rains/should rain.
Mother hid the sweets and chocolates lest/for fear that her son should see them.
7．結果狀語從句
1）結果狀語從句常由so that, so… that, such… that等引導，放在主句之后，so…that與such…that句型在一定條件下可轉換。例如：
The lift was out of order, so that we had to walk to the 18th floor.
He was so angry that he left the room without saying a word.
He made such an excellent speech that everyone admired him.
=He made so excellent a speech that everyone admired him.
在口語中也可用that引導結果從句。例如：
What have I said that he should be so angry with me?
2）so that引導結果狀語從句和目的狀語從句的辨別
so that從句之前有逗號的常為結果狀語從句，因表示某一行為帶來的結果，從句中的時態常為過去式；so that從句中有may(might), can(could), should, will等情態動詞的通常是目的狀語從句。例如：
I wrote as clearly as possible so that I might get high marks. （目的）
I wrote as clearly as possible, so that I got high marks. （結果）
He went to the lecture early so that he could get a good seat. （目的）
He went to the lecture early, so that he got a good seat. （結果）
8．方式狀語從句
1）方式狀語從句常由 (just) as, as if/though引導，表示動作的方式。
Do exactly as the doctor says.
He walked slowly as if/though he had hurt his leg.
注：在非正式文體中有時會用like代替as引導方式從句。
2）as if/though 引導的狀語從句，若描述非事實情況，常用虛擬語氣，若描述的是實際情況，用陳述語氣。例如：
She treats the orphan as if/though he were her own child.
（他是孤兒，當然就不是她的親生孩子，故用虛擬語氣。）
It looks as if/though it’s going to rain.
（本句用的是陳述語氣，說明天真象是要下雨了。）
3）the way 也可用來引導方式狀語從句。例如：
Mary smiled the way (in which/that) her mother did at her age.
（馬麗跟她母親在她那個年紀時笑起來一個樣。）
9．比較狀語從句
1）比較狀語從句常由as … as, not so (as) … as, than引導。比較從句部分常為省略句。例如：
His brother is as handsome as he (is)/him. （非正式英語中可用賓格him）
He swims faster than any other student in his class (does).
2）通常把the more…the more…結構也歸為比較從句，意為“越……越”。如：
The harder you work, the greater progress you’ll make.
The less she worred, the better she worked.
典型例題分析
1．If we work with a strong will, we can overcome any difficulty, ____ great it is. (’95)
A what B how C however D whatever
解析：本題考查-ever類詞引導讓步狀語從句的用法。根據句意“無論困難有多大”，排除答案A/B，whatever=no matter what，后面跟名詞或直接跟從句，however=no matter how，后跟形容詞或副詞，再接主語和謂語，故答案為C。
2．Mother was worried because Alice was ill, especially ____ Father was away in France. (’94)
A as B that Cduring D if
解析：根據前半句“媽媽因為Alice病了很著急”，后面有表示遞進意義的詞especially，順著句意推測，應該是“尤其是因為父親遠在法國”，表示原因，故答案為A。注意during是介詞，不能引導從句。
3．Why do you want a new job ____ you’ve got such a good one already? (’98)
A that B where C which D when
解析：本題考查when引導原因狀語從句的特殊用法。本句意為“既然你已經有了一個好工作，為什么還要找份新工作呢？”A/B/C都沒有表示原因的意思，不符合句意，故答案為D。
4．---What was the party like?
---Wonderful! It’s years ____ I enjoyed myself so much. (’93)
A after B before C when D since
解析：本題考查學生對”“It’s some time since sb. did sth.”結構的掌握，因一A/C般不用于此類句型，因此干擾最強的是before，而before常用句型為“It will be some time before sb. does sth.”，根據句子的意思及句中所用的時態，D為最佳選擇。
5．We won’t give up ____ we should fail ten times. (’93)
A even if B since C whether D until
解析：解本題的關鍵是弄清空格前后兩部分的關系，最佳的連接關系應該是“即使失敗十次，我們也不放棄。” 符合句意的只有答案A。
6．John shut everybody out of the kitchen ____he could prepare his grand surprise for the party.
A which B when C so that D as if (2002)
解析：分析句子意思，發現“John把每個人都關在廚房外”的目的就是為了“能夠準備他那別出心裁的晚會”，從句中的could是目的狀語從句的標志，因此答案為能夠引導目的狀語從句的so that ( C )。
7．After the war, a new school building was put up ____ there had once been a theatre. (’97)
A that B where C which D when
解析：分析題干和選項，不難發現句子要表達的意思，“戰后，在過去的劇院舊址上，新建了一所學校。”從空格到句末應該是一個表示地點的狀語從句，故答案為B。
8．It is generally considered unwise to give a child ____ he or she wants. (97’)
A however B whatever C whichever D whenever
解析：本題句中從空格處到句末為一賓語從句，作give的直接賓語，因此排除答案A和D，而whichever引導名詞性從句時， 所指代的名詞應是已知范圍內的人或物，通常在上文已經提到過或者在whichever后有該名詞或of結構。Whatever在引導名詞性從句時意為“anything that”，用于不定范圍的情況，本句意為“一般認為孩子要什么就給什么是不明智的”，不確指什么東西，因此答案為B。
摘自《新編名師導學》
蘇州市蘇苑中學 許鳳編寫