高中英语必修第三册Unit4语法精讲：动词不定式作状语和定语

高中英语必修第三册Unit4语法精讲：动词不定式作状语和定语
一、动词不定式在句中作状语,主要用来修饰动词和形容词,也可用来修饰副词。

在句中,不定式可作目的状语、原因状语、结果状语、条件状语等,可表示目的、原因及结果等。

1. 目的状语,置于句首或句末,置于句首时常表示强调。

为加强语气,常与inorder或soas 组成短语。

*A group of youngpeople got together to discuss this question.
一群年轻人聚在一起讨论这个问题。

*In order to helphim, we would do everything we can.
为了帮助他,我们将尽我们所能。

【名师点津】
不定式作目的状语
(1)置于句首时只用todo / in order to do。

如用于表示否定, in order 或so as不能省略,用in order not to do 或so as not to do形式。

*I walked quietlyso as not to disturb the baby.
我安静地走路,以免打扰婴儿。

(2)不定式作目的状语时,其动作通常迟于谓语动词的动作。

*I said that toencourage him.
我这么说是为了鼓励他。

(3)不定式作目的状语可转换为so that / in order that 或so. . . that . . . 引导的目的状语从句。

*He worked veryhard to pass the exam.
→He worked so hardthat he could pass the exam.
→He worked hard sothat/in order that he could pass the exam.
他非常努力以便能通过考试。

2. 结果状语,多见于“too.. . to”; “enough to. . . ”; only to do(表示意料之外的结果
的发生);so/such. . . as to(意为“如此……以至于……”)结构句中。

* I’m too tired todo well. 我太累了做不好。

*He is old enoughto go to school . 他到上学的年龄了。

*He rushed back,only to find the book missing.
他冲了回来,却发现书不见了。

* She is so proudas to look down upon others.
她太骄傲了,看不起别人。

3. 原因状语,多见于“sb.+be+adj. +to do. . . ”结构句中。

*I was very sad tohear the news.
听到这个消息我很难过。

4. 独立动词不定式多用作插入语,表示说话人的心理状态或对事情的看法。

*I’d like to stayhealthy, but to be honest, I only eat food that tastes good.
我想保持健康,但说实话,我只吃味道好的食物。

【名师点津】
现在分词与不定式作结果状语的区别
(1)动词不定式作结果状语强调的是一种意想不到的结果。

*Anxiously, shetook the dress out of the package and tried it on, only to find it didn’t fit.
(2)现在分词作结果状语强调的是一种顺承的,必然造成的结果。

*His father passedaway, leaving him a little money.
二、动词不定式用作定语
1. 名词前有first,last, next, only等词以及最高级修饰时, 其后要用动词不定式。

*She was the firstwoman to win the gold medal in the Olympic Games.
她是第一个在奥运会中赢得金牌的女性。

2. 动词不定式作定语常放在名词或不定代词后面作后置定语,表示尚未发生的动作。

*Let us give himsomething to eat.
让我们给他一些吃的东西。

*We have muchhomework to do tonight.
今晚我们有很多作业要做。

3. 当名词与定语之间存在动宾关系时。

*I usually have alot of meetings to attend.
我通常有很多会议要参加。

*She is a niceperson to work with.
她是一个很好的合作伙伴。

4. 抽象名词attempt,ability, chance, desire, determination, decision, plan, way或不定代词something,nothing等后面常用不定式作后置定语。

*But Janis Adkinshas the ability and desire to do useful work.
但是詹尼斯·阿德金斯有能力和愿望去做有用的工作。

5. 当名词与定语有同位关系时。

*We got the orderto leave the city.
我们接到了离开这个城市的命令。

6. 当名词与定语之间存在主谓关系时。

*We must find aperson to do the job.
我们必须找到一个人来做这项工作。

*We need someoneto go and get a doctor.
我们需要有人去请医生。

【知识延伸】
动词不定式作主语,表语和宾语
1. 不定式作主语,表示具体的某次动作。

若不定式结构比较复杂,常用it作形式主语,真正的主语放在句子的后面。

*To do morningexercises is useful for our health.
做早操对我们的健康有益。

*It’s importantfor us to learn English well.
学好英语对我们来说很重要。

2. 不定式作表语,表示将来的情况,说明主语的内容。

其主语常常是wish,idea, task, purpose, duty, job等表示意向、打算、计划的词。

*His dream is tobe a doctor.
他的梦想是成为一名医生。

*My work is toclean the room every day.
我的工作是每天打扫房间。

3. 不定式作宾语,常跟在某些动词后。

不定式作宾语的动词的记忆口诀:
决心学会选计划,拒绝答应想假装;
主动设法愿希望,同意请求帮一帮;
准备威胁易声称,渴望申请败踌躇。

其对应的动词分别为:
decide/determine,learn, choose, plan,
refuse, promise,want/attempt, pretend,
offer, manage,expect/wish/hope,
agree, ask/beg,help,
prepare, threaten,tend, claim,
desire/long,apply, fail, hesitate。

4. 若不定式结构比较复杂,通常用it 作形式宾语,真正的宾语放在句子的后面,该用法常见的动词有think,find, make, believe, consider, suppose, feel等。

*He can’t affordto buy the expensive car.
他买不起那辆昂贵的汽车。

*I think it usefulto learn a foreign language.
我认为学习一门外语是有用的。

*I feel it my dutyto say that you are wrong.
我觉得我有责任说你错了。

【巩固练习】
用所给单词的适当形式填空
1.The airport ________ (complete) next yearwill help promote tourism in this area.
2.The best way __________ (improve) yourEnglish is to join an English club.
3.Some scientists were determined to helphumans realise their dream________（explore）space.
4.—The last one________（ arrive ）pays the meal. —Agreed!
5.On 12 April 1961, Yuri Gagarin became thefirst person in the world ________（go） into space.
6.With the world changing fast, we havesomething new________（deal ）with all by ourselves every day.
7.A group of young people got together ________（ discuss） this question.
8.First of all, you must be intelligentenough________（ get） a related college degree.
9.He got up late and hurried to his office,________（leave）the breakfast untouched.
10.Anxiously, she took the dress out of thepackage and tried it on, only______ （ find）it didn’tfit.
11.When the gorillas and I frightened eachother, I was just glad
______(find) them alive.
12.The question was very difficult ________（answer）.
13.The box is light enough ________（ carry）.
14._________(work out) the difficult mathsproblem, I have consulted Professor Russell several times.
15.________(learn) more about Chineseculture, Jack has decided to take Chinese folk music as an elective course.
答案：
1. to be completed
2.to improve
3.to explore
4. toarrive
5.to go
6. to deal
7. to discuss 8. to get 9 .leaving 10.to find 11.tofind 12.to answer
13.to carry
14.To work out 15. To learn。