由從句擔(dān)任的狀語，在句子中可修飾謂語(或其他動詞)、形容詞、副詞或是整個(gè)句子，它可以用來表示時(shí)間、地點(diǎn)、原因、目的、結(jié)果、條件、方式、比較、讓步 等。狀語從句是一較大的語法項(xiàng)目，也是近幾年高考題中常見的一個(gè)重要試點(diǎn)。高考中已考查了時(shí)間、讓步、地點(diǎn)、條件、目的等狀語從句，這些從句仍是今后高考 熱點(diǎn)，應(yīng)作充分準(zhǔn)備。同時(shí)對方式狀語從句也應(yīng)引起重視。
一、時(shí)間狀語從句
表示時(shí)間的狀語從句可由when， as， while， whenever， after， before， till (until)， since， once， as soon as (或the moment )， by the time， no sooner …… than， hardly (scarcely) …… when， every time等引導(dǎo)。
e.g. When I came into the office， the teachers were having a meeting.
He started as soon as he received the news.
Once you see him， you will never forget him.
No sooner had I gone to bed than I went to sleep.
二、原因狀語從句
原因狀語從句是表示原因或理由的，引導(dǎo)這類從句的最常用的連詞是because， since， as ， now that(既然)等，for 表示因果關(guān)系時(shí)(它引導(dǎo)的不是從句)為并列連詞，語氣不如because強(qiáng)。
e.g. He is disappointed because he didn‘t get the position.
As it is raining， I will not go out.
Now that you mention it， I do remember.
三、地點(diǎn)狀語從句
引導(dǎo)地點(diǎn)狀語從句的連詞是where 和wherever等。
e.g. Sit wherever you like.
Make a mark where you have a question.
四、目的狀語從句
引導(dǎo)目的狀語從句最常用的詞(組)是so， so that(從句謂語常有情態(tài)動詞)， in order that， in case(以防，以免)等。
e.g. Speak clearly， so that they may understand you.
She has bought the book in order that she could follow the TV lessons.
He left early in case he should miss the train.
五、結(jié)果狀語從句
結(jié)果狀語從句是表示事態(tài)結(jié)果的從句，通常主句是原因，從句是結(jié)果。由so that(從句謂語一般沒有情態(tài)動詞)， so …… that， such …… that等引導(dǎo)。
e.g. She was ill， so that she didn’t attend the meeting.
He was so excited that he could not say a word.
She is such a good teacher that everyone admires her.
六、條件狀語從句
條件狀語從句分真實(shí)性(有可能實(shí)現(xiàn)的事情)與非真實(shí)性(條件與事實(shí)相反或者在說話者看來不大可能實(shí)現(xiàn)的事情)條件句。引導(dǎo)條件狀語從句的詞(組)主要有 if， unless， so (as) long as， on condition that， so (as) far as， if only ( = if )。注意：條件從句中的if 不能用whether替換。
e.g. If he is not in the office， he must be out for lunch.
You may borrow the book so long as you keep it clean.
So far as I know(據(jù)我所知)， he will be away for three months.
You can go swimming on condition that ( = if ) you don‘t go too far away from the river bank.
If he had come a few minutes earlier， he could have seen her.
七、讓步狀語從句
讓步狀語從句可由although， though， as， even if (though)， however， whatever， whether …… or， no matter who (when， what， ……) 等引導(dǎo)。注意：as引導(dǎo)的讓步狀語從句一般是倒裝的。
e.g. Though he is a child， he knows a lot.
Child as he is， he knows a lot.
Whatever ( = No matter what ) you say， I’ll never change my mind.
八、方式狀語從句
方式狀語從句常由as， as if (though)， the way， rather than等引導(dǎo)。
e.g. You must do the exercise as I show you.
He acted as if nothing had happened.
九、比較狀語從句
比較狀語從句常用than， so (as) …… as， the more …… the more等引導(dǎo)。
e.g. I have made a lot more mistakes than you have.
He smokes cigarettes as expensive as he can afford.
The busier he is， the happier he feels.
十、使用狀語從句時(shí)要注意的幾個(gè)問題
1. 在時(shí)間和條件(有時(shí)也在方式、讓步等)從句中，主句是一般將來時(shí)，從句通常用一般現(xiàn)在時(shí)表示將來。
e.g. We‘ll go outing if it doesn’t rain tomorrow.
I‘ll write to you as soon as I get to Shanghai.
2. 有些時(shí)間、地點(diǎn)、條件、方式或讓步從句，如果從句的主語與主句主語一致(或雖不一致，是it)，從句的謂語又包含動詞be，就可省略從句中的“主語 + be”部分。
e.g. When (he was) still a boy of ten， he had to work day and night.
If (you are) asked you may come in.
If (it is) necessary I’ll explain to you again.
3. 注意區(qū)分不同從句：引導(dǎo)的是什么從句，不僅要根據(jù)連詞，還要根據(jù)句子結(jié)構(gòu)和句意來判別。以where為例，能引導(dǎo)多種從句。
e.g. You are to find it where you left it.(地點(diǎn)狀語從句)
Tell me the address where he lives.(定語從句，句中有先行詞)
I don‘t know where he came from.(賓語從句)
Where he has gone is not known yet.(主語從句)
This place is where they once hid.(表語從句)
