九年级英语Unit13《We27re trying to save the earth》知识点

九年级英语Unit13《We're trying to save the earth!》知识点
1.现在进行时
定义：表示说话时（瞬间）正在进行的动作，也表示目前或现阶段一直进行的动作。

结构: ①肯定句: 主语+ am/is/are + V-ing
②否定句: 主语+ am/is/are + not + V-ing
③疑问句: Am/Is/Are + 主语+ V-ing
用法：1）表示说话时正在进行的，目前正在发生的动作。

①Look! The big bird is flying away. ②He is watching a movie now.
2）表示目前一段时间内正在进行，但说话时可能没有进行的动作。

Right now I am studying Chinese by distance learning. 我现在正通过远程教育学习汉语。

1) 2)常带有表示目前时刻的时间副词, 如：now, right now, at the (very) moment, for the time being, at present, these days 及Look! Listen! ...
3）与always, constantly, forever, all the time等副词连用，表示动作反复或习惯。

此时句子常含有说话者的强烈情感在内。

表达较强的“责备”或“表扬”之意
①You are always changing your mind. 你总是主意不定。

(太烦人了)
②He is always helping others.他总是帮助别人。

(他真是个好人)
4）对于come, go, leave, arrive, start, fly, drive等表示位置移动的动词常可用进行时态表将来。

①He is leaving on Wednesday.
②Mary isn’t here at the moment. She is coming later.
2. used to do过去常常做某事见第四单元及use用法
be/get used to doing 习惯于做某事
be used to do=be used for doing 被用来做某事
3. 被动语态见第五单元
注意：接双宾语的词的被动语态；make /let /have sb do的被动语态；see/ hear /notice /find /observe/notice sb do 的被动语态；It’s
said/reported/believed/supposed/well-known that；及无被动语态的三种情况（感官动词、不及物动词、sell/write等）
4. 现在完成时: 用法：①过去发生的动作对现在造成的影响或结果：强调结果
Yesterday I finished my homework, that’s to say, I have finished my homework now.
②过去已经开始一直持续到现在的动作或状态：强调继续
I have lived here since 1990.
现在完成时的构成have/has+过去分词
现在完成时的四个基本句型
肯定句He has finished the work.
一般疑问句Has he finished the work?
否定句He has not finished the work.
两回答Yes ,he has. No, he hasn’t.
特殊疑问句What has he done?
在下列情形下用现在完成时
1九词语
①already 已经肯定句中或句尾I have already found my pen. = I have found my pen already.
②yet已经否定句和疑问句句尾I have not finished the work yet.
Have you bought a computer yet?
③ever曾经句中Have you ever seen pandas?
④never从不句中I have never been to Beijing.
⑤just刚刚句中I have just done my work.
⑥before以前句尾I have never been there before.
⑦so far到目前为止So far he has learned 200 words.
⑧how long多久How long have you lived here?
⑨how many times多少次How many times has he been to Beijing?
2两词组
have<has>gone to去了某地例：He has gone to Beijing (去了北京，没回) have<has>been to去过某地例：He has been to Beijing. (去过北京，回了) 3两结构
for two months for +一段时间 Jim has lived here for 2 months.
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since last year since +过去时间点 Lucy has been in Beijing since 3 years ago. since 3 years ago
since 1990
since he came here since +过去时态句子 He has been in China since he came here.
4如果句子里面没有时间状语，汉语意思能够加“已经”，往往用现在完成时态。

Have you lost your library book? 你已经弄丢了从图书馆借的那本书吗？
5现在完成时态还常常用于下列句型
They have planted many trees in the last/past few years.
This is the best book I have ever read.
It is the first time I have played the computer games.
在现在完成时中，一次性动词不能和一段时间状语连用
例：He has bought the book for 3 years.（错）
因buy这个一次性动词不能和一段时间for 3 years连用, 改正的办法有：
He has bought the book. (去掉一段时间for 3 years)
He bought the book 3 years ago (改为一般过去时，使句子的意思不变)
It’s/It has been 3 years since he bought the book. = 3 years has pass ed since he bought the book. （改为固定句型It is/It has been ---since---）He has had the book for 3 years.
（用延续性动词have代替buy）
另外
①come/arrive/get to/reach → be here
I have come here for 3 years.（错）
改为：I have been here for 3 years.
②leave/go →be away
He has left for 3 hours.（错）
改为：He has been away for 3 hours.
③begin/start →be on
The film has begun for 3 minutes.（错）
改为：The film has been on for 3 minutes. ④open →be open / close → be closed
The shop has opened for 3 years.(错)
改为：The shop has been open for 3 years.
⑤die →be dead
His father has died for 3 years.(错)
改为：His father has been dead for 3 years.
⑥finish/end→ be over
He has finished the work for 3 days.(错)
改为：The work has been over for 3 days
⑦join I have joined the army for 3 years.（错）
改为：I have been in the army for 3 years.
或I have been a soldier for 3 years.
⑧buy /catch → have
I have bought the bike for 3 years.（错）
改为：I have had the bike for 3 years.
He has caught a cold for 3 days.（错）
改为：He has had a cold for 3 days.
⑨borrow → keep
I have borrowed the book for 3 years. （错）
改为：I have kept the book for 3 years.
还有其它的归纳如下：
break → be broken get up → be up marry → be married become → be lose → be lost
5. 情态动词
1) 情态动词本身有一定的词义，表示说话人的情绪、态度或语气，但不能单独作谓语，只能与其他动词构成谓语。

常见的有：can (could), may (might), must, need, shall (should), will (would)等。

2) 情态动词无人称和数的变化, 后接动词原形。

否定式是在情态动词后面加not。

个别情态动词有过去式形式, 也可用来表达更加客气、委婉的语气。

1.can和could的用法
文案
(1)can/could 表示“能力；许可；可能性”等。

could 为can 的过去式。

如：Can I use your bike?
(2)can 用在疑问句中，表示征求意见、请求许可，答语仍用can; could 用在疑问句中，比can 更委婉、客气，是一种礼貌的说法，并不表示过去时态，答语用can，而不能用could。

如：—Could you tell me the way to the zoo?—Sorry. I can't. I'm new here。

[注意] can 和could 只能用于现在时和过去时两种时态，将来时中用be able to。

另外，can't 可表示否定推测。

如：That ______ be Mr Wang. He has gone to Beijing。

2.may和might的用法
may/might 意为“可以”，表示同意、许可或请求对方许可，也可表示祝愿。

may的否定形式为may not。

might 是may 的过去式，有两种用法：一种表示过去式；一种表示虚拟语气，使语气更加委婉、客气，或表示可能性更小。

以may开头的一般疑问句，其否定回答用mustn't, 而不用may not。

如：______ I use your pen? 我可以用你用的钢笔吗？
You may put on more clothes. May you be happy!
Might I borrow some money now?He might be alive.
3.must的用法
must 意为“必须，一定，准是”，表示说话人认为有必要做某事，或命令、要求别人做某事以及对事物的推测。

否定形式mustn't, 表示“不得”，“一定不要”。

如：
I ______ finish my work today。

You mustn't drive after drinking。

(1)must 与have to 的区别：must 表示说话人的主观意愿；have to 表示客观需要。

如：
I must do my homework first。

It is raining hard outside; I _____ stay at home。

(2)回答由must 引导的疑问句的提问
①肯定回答：Yes, …must.如：
—Must I go home now? —Yes, you must.
②否定回答：No，…needn't./No，…don't/doesn't have to.
—Must I go home now? —No, you __ ____.
(3)must 表示对事物的推测，意为“想必；一定”，只用于肯定句中；表“推测”时，情态动词与动词原形，(常为be动词)连用，如：The man must be our teacher。

4.need的用法
(1)need 表示“需要，必须”，主要用于否定句和疑问句中。

其否定形式为needn't，表示“没有必要，不必”；对由need构成的疑问句进行回答时，其肯定回答用must，否定回答用needn't。

如
—Need we do some cleaning now?
—Yes, you must. —No, you needn't.
(2)need 还可作实义动词，常用于下列结构：
①人：need to do sth“需要做某事”。

如I need to learn more.
②物：need doing “某物需要被做”=need to be done。

如：My hair needs cutting. =My hair needs to be cut.
③need +名词或代词。

如：All living things need water.
5.shall和should的用法
shall 用于第一人称的句子中，表示提建议或请求；should用于各种人称的句子中，强调义务或责任，意为“应该”。

如：______ we go out for a walk?
You should study hard at school。

should have done主要有两个用法：
用于推测过去已经发生的情况。

如：He should have arrived by now.
用于指本该发生而实际上未发生的情况。

如：You should have told me so before.
6.will和would的用法
will用于第二人称疑问句时，表示征求意见或提建议；would 为will 的过去式，可用于多种人称，表示意愿。

如：Will you have a little soup?
would have done主要有两个用法：
表“猜测过去”
I guess the poet would have been about twenty when she wrote her first poem. 表“过去本会发生，而实际并未发生”，没有责备之意。

I would have written before but I have been ill.本来我是会写信的，但是由于我生病了。

（用来说明某一情况，没有责备之意）
7.have to
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have to 的陈述句形式
肯定式：have to + 动词原形I have to tidy my room.我得整理房间.
否定式：don't (doesn't) + have to + 动词原形You don't have to go if you don't want to.
have to 的一般疑问句形式及简略答语
have to的一般疑问形式必须借助助动词do 或does：
Do you have to look after your sister? Yes,I do./ No,I don't.
have to 的特殊疑问句形式What do you have to do on Sundays?
have to 可用于各种时态
A、一般现在时：I have to visit Mr Wang.
B、一般过去时：That night we had to walk home because there was no bus.
C、一般将来时：We'll have to ask Zhang Ming instead.
D、与may 连用：I think he may have to help his Dad in the garden.
8.ought to
ought to的肯定式应当, 应该
You don't look well. You ought to go to see the doctor.
ought to的否定式和疑问式
ought to的否定形式是ought后直接加not构成，其否定形式可缩写为oughtn't。

One ought not (oughtn't) to cross the street against the red light.
ought to的疑问式是将ought提到句首构成。

—Ought we to do it at once? —Yes, you ought to.
He ought to be here now, shouldn't (oughtn't) he?
“ought to + have + done”表示过去应做某事而实际未做
You ought to have told me that (but you didn't).这时ought to和should可以互换使用。

三．
1.litter/rubbish/garbage/waste/trash
garbage和rubbish含义相同，garbage美国英语，而rubbish英国英语。

这两个词词义较为具体，指必须及时清除的剩余物，比如厨房里的垃圾，生活垃圾等等。

litter指公共场所丢弃的小片/块垃圾，如纸片、塑料袋、易拉罐、饮料瓶等。

waste作名词用时可表“废物”的总称。

另：waste time in doing sth浪费时间做某事
take out the trash倒垃圾
2.at the bottom of在...底部/at the top of在...顶部
He shouted at the top of his voice in order that he might be heard.
3.advantage-disadvantage
1). have/gain/get the (an) advantage over (of) 优于，比……占有优势。

如：You have the advantage over (of) me in experience.
你经验比我丰富。

有时用动词gain, get 等。

如：
They gained an advantage over the enemy. 他们比敌人占优势。

2). take advantage of=make (full) use of
(1) 利用(机会、时机等)。

They took advantage of the fine weather to play tennis.
(2) 利用(某人的处境、弱点等)。

He always took full advantage of the mistakes made by his rivals.
(3) 欺骗(某人)，捉弄(某人)，占(某人的)便宜。

He has always been taking advantage of me.
3). to sb’s advantage对某人有利。

It will be to your advantage to study abroad.
4.四个花费句型
人：spend 钱/时间on sth. spend 钱/时间in doing sth. spent
人：pay 钱for sth. pay-paid-paid
物：sth. cost sb. 钱cost-cost-cost
It takes sb. 时间to do sth. take-took-taken
5.be harmful to=do harm to对…有害
Smoking is harmful to the health.
= Smoking does harm to your health
6.参加辨析
join join in & take part in attend
7.afford to do sth担负得起干某事[常与can, could, be able to 连用]
文案
He told me that the firm could not afford to pay such large salaries.
他告诉我公司无法支付如此巨额的工资。

8.turn 短语
turn in 归还You must turn in your equipment before you leave the army. turn on 打开could you turn on the light, please？turn off 关掉（煤气，水，电，收音机，电视机等）Don’t forget to turn off the light when you leave. turn up ①出现，到达②开大音量He promised to come but hasn’t turned up yet. I can’t hear the radio very well; could you turn it up a bit？turn down ①关小②拒绝(refuse) Can you turn the TV down? I’m trying to get some sleep. He tried to join the army but was turned down because of poor health. turn out (to be) +adj./n.证明是，结果是The experiment turned out to be a great success. turn/change into 把……变成，译成Turn the following sentences into Chinese, please. turn to 翻到，求助于1)Please turn to page10. 2)The child turned to his mother for comfort. turn over 翻身，翻转She turned over and went to sleep.
9.throw away扔掉,丢弃错过(机会、优势或好处)
He threw away the old sofa. Don't throw away this opportunity.
10.work
work n.工作；（音乐、艺术）作品；工厂v. 工作
He has much work to do.(U)
The man gained his wealth by printing works of famous writers.
（做“作品”讲，为可数名词，但常用复数）
The glass works is/are near the station.
玻璃厂在车站附近。

（做“工厂”讲，只用复数形式，但谓语动词单复均可）
英语中有些名词，单复数形式意义有差别。

manner 方式，方法manners 礼貌，礼仪
arm 胳膊arms 武器
water 水waters 海水，水域
wood 木头woods 森林
11.bring back归还；使想起
These books must be brought back within a week．Your article brought back sad memories for me.
bring up：抚养长大bring in：引进bring forward：提出bring about：带来，造成
12.inspiration n inspire v激励
13.try to do =try/do one’s best to do 努力去做某事。

try doing sth. 尝试做某事
Every student should try to study hard in order to study in a university.
14.be related to 与…有关
I am not related to him in any way. 我和他无任何关系。

15. play a part in doing sth 在……方面起作用
A good diet plays a large part in helping people live longer.
16.turn/change… into…
(使)变成Joan is turning into quite a skilled musician.
译成Please turn this into English.
17. make a difference (to…) 表示(对……)产生影响或作用The new teacher always encourages little Tom. This has made a big difference to him.
18. no longer意思是“不再”
有两个短语和no longer同义，即not…any longer和not…any more，但他们侧重的方面不同。

no longer和not…any longer侧重时间。

e.g. He no longer lives here.= He doesn’t live here any longer.
他不在这儿居住了。

(一个时间以前他住在这儿，过了这个时间，他就离开了。

) not…any more =no more侧重侧重程度和数量
You can drink n o more. = You can’t drink any more.
你不能再喝了。

(喝酒的量到了一定程度，不能再继续下去了。

)
19.not only…but also…“不仅……而且……”;
其中的also有时可以省略。

若连接两个成分作主语，其谓语通常与靠近的主语保持一致。

Not only you but also he has to leave. 不只是你，他也得离开。

not only放在句首，后接句子时要用倒装结构。

文案
Not only did my aunt teach at school, but (also) she wrote articles for newspapers.
20.The number of......的数量，谓语用单三
a number of...大量的，谓语用原形
当表示数值的高或低时，number要用high或low修饰。

当表达数量多，少large/small
In that country, the number of children going to school is higher in cities than in towns and village.在那个国家，城市儿童入学人数比乡镇及农村要高。

常与number搭配的动词有grow, fall等。

The number of families that own cars has been growing quickly recently.
近来拥有轿车的家庭数量增长很快。

21.put sth. to good use 好好利用
22.build/make ... out of 用……建造/制造
He built a model ship out of wood. 他用木头造了个模型船。

23.The top of the house is an old boat turned upside down.
turned upside down 意为“被翻转过来的；被颠倒过来的”，做后置定语修饰boat。

24.be made of和be made from
25. be known for 因……而著名
be known as 作为……而著名
be known to 对于某人来说是著名的
26.bring sb/sth back to life 使复活，给…以活力;
27. Rethink, Reuse, Recycle, Reduce!
re-是最常用的前缀之一re-表示以下三方面的意义：
1)表示“回”或“向后”的意思。

return（回来）recall（回忆，召回）retract（缩回，取回）
2)表示“再”、“重新”、“重复”的意思。

rethink（再思考）reuse（再运用）restart（重新开始）recycle（再利用）
3)表示“相反”、“反对”的意思。

rebel（反叛，谋反）reverse （反转，颠倒）resist （反抗，抵抗）
28. She is a most unusual woman.
un-前缀，第一，表示否定意义。

第二，表示“反动作”。

即“相反的动作”。

uncomfortable不舒服的unending无尽的unfortunate不幸的unusual不平常的unkind不仁慈的unbind解开，释放uncover揭开……的盖子unearth由地下掘出unbutton 解开钮扣
29.-ive是形容词后缀一般表示有......的create ﹢-ive = creative
30.recent ﹢-ly = recently形容词加ly变副词
31.Amy is an inspiration (n.灵感) to us all.
后缀-tion附在动词后面构成名词
1)当单词最后是t, d, te, de时，变名词加tion或者ation, ition；
2)当单词最后是元音字母时，变名词加sion等。

32. cut down 砍倒，减少
The little boy cut down the young tree with an axe
The doctor told me to cut down smoking and drinking.
cut up 切碎
cut off切断，停止
33.especially 尤其，特别
be full of =be filled with 充满
noise/air/water/land pollution 噪音，空气，水，陆地污染
throw...into... 扔进
cause the problem 引起麻烦
write to sb.=write a letter to sb.=write sb. a letter给某人写信
clean up 打扫干净
used to do 过去常常做某事
too much太多+U/too many太多+Cs/much too太..
play a part in
cut down
instead of+doing 代替rather than
make a difference
around here=near here 在附近
lead to 导入
idea for doing sth.
文案
solve the problems解决问题solution n.解决
take the+交通工具=by+交通工具
help/work起作用
remember to do/doing forget to do/doing
hear of /about 听说
hear from sb.=get/receive a letter from sb. 收到某人来信
be harmful to=do harm to
the food chain 食物链
the whole +n=all the + n
be in danger=be endangered
fall by over 90 percent 下降90%
increase by 是增加了多少increase to 是增加至多少
in the last/past 20 years 在过去的20年
begin with sth 以…为开始
add up 累加add… to…加…
stop to do/doing
take action 采取行动
pull…down 拆迁推到
set up=establish 建立
the best way to do sth = the best way of doing做某事的最佳方法
34．
Write a letter to the city major about the problem and your suggestions.
In your letter, describe the environmental problems in your town/city.
①What are the problems?②Where are they?③What or who is causing these problems?
Then, give suggestions or possible ways to solve the problems.
I think that… We should/ could… I suggest…
Dear Sir/ Madam,
Environmental problems are becoming more and more serious all over the world. With the development of the society, there are too many cars on the streets in our city. Cars have made the air unhealthy for people to breathe. Black smoke and poisonous gas are given off by factories. Factories also put waste into the river. And wherever we go, we can find rubbish.
Now more and more people have realized these problems. I think that governments should close down the factories and develop laws to stop people from driving cars every day. I suggest everyone in this town should help to clean up the river and the streets. We should call on everyone in the town to throw rubbish in the dustbins.
I hope the problem will be solved in the near future and our home will become better and better.
35. land pollution 土地污染
36. fill the air with black smoke 使空气中充满了黑烟
37. use public transportation 使用公共交通
38. recycle books and paper 回收书和废纸
39. use paper napkins 使用纸巾
【重点句子】
1. Even the bottom of the river was full of rubbish. 即使河底都充满垃圾。

2. Everyone in town should play a part in cleaning it up. 城里的每个人都应当尽一份力把它清理干净。

3. The air is badly polluted because there are too many cars on the road these days.
空气被严重污染因为如今路上的汽车太多了。

4. To cut down air pollution, we should take the bus or subway instead of driving.
为了减少空气污染，我们应当乘坐公汽或地铁而不是开车。

5. I used to be able to see stars in the sky. 我过去能在天空中看到星星。

6. The air has become really polluted around here. I’m getting very worried.
这儿的空气真的已经被污染了，我非常担心。

7. No scientific studies have shown that shark fins are good for health.
没有科学研究说明鱼鳍对人们的健康有好处。

【单元知识点】
文案
1. cost vt.1. 花费；价格为；值
例句：It must cost a good deal to live here. 住在这里一定要花很多钱的拓展：take，spend ，cost ，pay的用法都可以表示“花费”，但用法却不尽相同。

1）spend的主语必须是人，常用于以下结构：
（1）spend time ／money on sth. 在……上花费时间（金钱）。

例：I spent two hours on this maths problem. 这道数学题花了我两个小时。

（2）spend time ／money （in）doing sth. 花费时间（金钱）做某事。

例：They spent two years （in）building this bridge. 造这座桥花了他们两年时间。

（3）spend money for sth. 花钱买……例：His money was spent for books. 他的钱用来买书了。

2）cost的主语是物或某种活动，还可以表示“值”，常见用法如下：
（1）sth. costs （sb.）＋金钱，某物花了（某人）多少钱。

例：A new computer costs a lot of money. 买一台新电脑要花一大笔钱。

（2）（doing）sth. costs （sb.）＋时间，某物（做某事）花了（某人）多少时间。

例：Remembering these new words cost him a lot of time. 他花了大量时间才记住了这些单词。

注意：cost的过去式及过去分词都是cost,并且不能用于被动句。

3）take后面常跟双宾语，常见用法有以下几种：
（1）It takes sb. ＋时间＋to do sth. 做某事花了某人多少时间。

例：It took them three years to build this road. 他们用了三年时间修完了这条路。

（2）doing sth. takes sb. ＋时间，做某事花了某人多少时间。

例：Repairing this car took him the whole afternoon. 他花了一下午修车。

4）pay的基本用法是：
（1）pay （sb.）money for sth. 付钱（给某人）买……例：I have to pay them 20 pounds for this room each month. 我每个月要付20英磅的房租。

（2）pay for sth. 付……的钱。

例：I have to pay for the book lost. 我不得不赔丢失的书款。

（3）pay for sb. 替某人付钱。

例：Don?蒺t worry!I'll pay for you. 别担心，我会给你付钱的。

（4）pay sb. 付钱给某人。

例：They pay us every month.他们每月给我们报酬。

（5）pay money back 还钱。

例：May I borrow 12 yuan from you? I'll pay it back next week. 你能借给我12块钱吗？下周还你。

（6）pay off one's money还清钱。

2. This method is not only cruel, but also harmful to the environment.
这种方法不仅残酷，而且对环境有害。

（1）not only…but also…意为“不仅……而且……”用于连接两个表示并列关系的成分，着重强调后者，其中的also有时可以省略。

如：She not only plays well, but also writes music. 她不仅很会演奏，而且还会作曲。

He not only writes his own plays, he also acts in them. 他不仅是自编剧本，还饰演其中的角色。

He works not only on weekdays but on Sundays as well. 他不仅平时工作，星期日也工作。

（2）若连接两个成分作主语，其谓语通常与靠近的主语保持一致。

如：Not only you but also he has to leave. 不只是你，他也得离开。

（3）若连接两个句子，not only后面的句子要用倒装，
如：Not only did he speak more correctly, but he spoke more easily. 他不仅说得更正确，而且讲得更不费劲了。

3. work n. （音乐，艺术）作品
work的用法
作名词
1) 不可数，意为：工作；劳动；作业；功课事，成果，产品；工艺品，针线活
如：It takes a lot of work to dig a deep well. 挖一口深井很费事。

I have to bring my work home today. 今天我得把工作带回家做。

2) 作可数名词着作，作品
He is making a study of William Faulkner's works. 他在研究威廉•福克纳的作品。

文案
作不及物动词（vi.）
1) 工作，劳动，干活[（+at/on）] She works in a restaurant.她在一家饭店工作。

2) （机器等）运转，活动
The machine won't work.机器不转了。

3) （由于使用等）逐渐变动；慢慢地前进
4) 起作用；行得通
Your suggestion works well. 你的建议很有效。

作及物动词（vt.）
1) 使工作，使干活
Don't work yourself to death. 别拼命做了。

2) 开动；操作
Please tell me how to work the machine. 请告诉我如何操纵这机器。

3) 通过努力取得；靠做工取得
4) 使缓慢前进；使逐渐变动
Can you work the screw loose? 你能使这个螺钉松开吗？
5) 造成，引起；激起
This scientist worked miracles. 这位科学家创造了奇迹。

6)安排，经营，管理
He worked the farm with great success. 这个农场他经营得很成功。

8) 影响；说服
I'll try to work him to my way of thinking. 我要设法说服他同意我的想法。

9) 精工细做
10) 计算，算出
【语法归纳】
动词不定式做目的状语时的用法
To cut down air pollution, we should take the bus or subway instead of driving.
为了减少空气污染，我们应当乘坐公汽或地铁而不是开车。

本句中To cut down air pollution是动词不定式作目的状语。

动词不定式做目的状语时的用法
一、不定式和不定式短语作目的状语
不定式和不定式短语作目的状语，主要用来修饰动词，表示某一动作或状态的目的。

为了使目的意义更加清楚或表示强调意义时，还可以在前面加in order to 或so as to。

例如：
I've written it down in order not to forget.
He shouted and waved so as to be noticed.
在句子中作谓语动词的状语的不定式或不定式短语，表示的是主语的目的，因此，其逻辑主语通常是句子的主语。

比较：
To draw maps properly, you need a special pen.（正）
To draw maps properly, a special pen is needed.（误）
由in order to 引导的目的状语，既可以置于句尾，也可以置于句首，而由so as to 引导的目的状语，只能置于句尾，而不能置于句首。

比较：
They started early in order to get there in time.（正）
In order to get there in time, they started early.（正）
They started early so as to get there in time.（正）
So as to get there in time, they started early.（误）
二、不定式的复合结构作目的状语
当不定式或不定式短语有自己的执行者时，要用不定式的复合结构（即在不定式或不定式短语之前加for + 名词或宾格代词）作状语。

例如：
He opened the door for the children to come in.
She fetched several bottles which she placed on the counter for Harry to inspect.
三、目的状语从句与不定式的转换
英语中的目的状语从句，还可以变为不定式或不定式短语作状语，从而使句子在结构上得以简化。

可分为两种情况：
1. 当目的状语从句中的主语与主句中的主语相同时，可以直接简化为不定式或不定式短语作状语。

例如：
We'll start early in order that/so that we may arrive in time.
We'll start early in order to/so as to arrive in time.
2. 当目的状语从句中的主语与主句中的主语不相同时，要用动词不定式的复合
文案
结构作状语。

例如：
I came early in order that you might read my report before the meeting.
I came early （in order）for you to read my report before the meeting. 文案。