定义

不定式由“to＋动词原形”构成，有时to可以省略，其否定形式是“not to do”。不定式没有人称和数的变化，但有时态、语态的变化。不定式不能作谓语，但可以作主语、宾语、状语、表语、定语和补语，本章节主要讲解不定式作定语和状语的用法。

动词不定式的形式

形式	主动	被动
一般式	to do	to be done
进行式	to be doing
完成式	to have done	to have been done
完成进行式	to have been doing

1.不定式的一般式：表示不定式的动作与谓语动词同时（几乎同时）发生或在谓语动词之后发生。

I hope to see you next week. 我希望下周能见到你。

I’d like to be told what’s going on. 我希望被告知正在发生什么。

2.不定式的进行式：表示不定式的动作与谓语动词同时发生且正在进行。

I happened to be watching TV when she called. 她打电话来时，我恰巧正在看电视。

3.不定式的完成式：表示不定式的动作发生在谓语动词之前。

They seem to have cleaned the house. 他们似乎已经打扫过这座房子了。

The factory is reported to have been burnt down. 据报道这家工厂已经被烧毁了。

4.不定式的被动语态：不定式的逻辑主语是不定式所表示的动作的承受者而非发出者。

She felt puzzled to be asked such a question. 被问了这样一个问题，她很疑惑。

不定式作定语

1.不定式作定语，置于被修饰词之后，常表示未发生、将来的动作。

I have many letters to write. 我有许多信要写。

The car to be bought is for his sister. 要买的这辆车是给他姐姐的。

2.在序数词、形容词最高级、顺序词（the last，the next等）、the only、等修饰的名词/代词后用不定式作后置定语。(动词不定式与被修饰词之间有逻辑上的主谓关系)

She was the first woman to win the gold medal in the Olympic Games. 她是第一个在奥运会上获得金牌的女性。

Lily was the only one to stay for the whole speech. Lily是唯一一个整场讲座留下来的人。

The youngest person to enter this university was just fourteen. 进入到这所大学年纪最小的人只有十四岁。

3.不定代词（something，anything等）习惯上用不定式作定语。例如：

Though we have made great progress, there is still much to be improved. 虽然我们取得了很大的进步，但仍有许多地方需要改进。

Have you got anything to cure my bad cold. 你有治疗我重感冒的东西吗？

4.在某些由动词、形容词派生的名词，由于他们的词根配不定式（如decide to do; be able to do; plan to do)，因而这些名词后也常接不定式作定语，常见的有∶decision、ability、plan、promise、plan、offer、warming、attempt，willingness，tendency等等。

Does he have the ability to do the job? 他有做这份工作的能力吗？

I don’t trust his promise to come for a visit. 我不相信他来这参观的承诺。

She said she had no plans to go there. 她说她没有去那里的打算。

5.用于说明某些名词的内容，这类词有：chance，opportunity，reason，courage，way等。例如：

We have a good reason to believe that he is lying.我们有很好的理由相信他在说谎。

You must have the courage to say “No”.你必须要有说“不”的勇气。

注意：

1、作定语的不定式如果是不及物动词，或不定式所修饰的名词或代词是不定式动作的地点、工具等，不定式后面需有相应的介词。

I am looking for a room to live in. 我正在找一间房子住。

Can I borrow a pen to write with? 我可以借一只可以写字的笔吗？

2、不定式作定语需要后置。

3、作定语的不定式与被修饰的名词或代词存在着三种主要的逻辑关系，即被修饰的名词和代词是不定式的逻辑主语(逻辑上的主谓关系)或逻辑宾语(逻辑上的动宾关系)或修饰性关系(同位关系)。

①动宾关系：

I have a lot of work to do(要做)．

Give me a piece of paper to write on(写).

②主谓关系：

Women and children were the first to get into the lifeboat(登上救生艇)．

③修饰性关系：不定式前的名词是它修饰的对象，它所修饰的词多为抽象名词，如：need, time, way, right, chance, courage, reason, wish, movement…

There is no need for him to come.

He has no time to read the book.

[提示]　为动宾关系的不定式，必须是及物动词或不及物动词加介词；如果不定式所修饰的词是way或place，介词可省略。

It is a comfortable sofa to sit on.

He has no way to go.

This is the best place to work

不定式作状语

不定式由“to+动词原形”构成，其否定形式是“not to do”。

不定式可以在句子中作状语，通常可用来表示目的、结果、原因等，其逻辑主语就是句子的主语。

 1.不定式作目的状语

They came here to seek a new life.他们来这里寻求一种新生活。

 He started early in order not to be late.为了不迟到，他早早就动身了。

不定式前可加in order或者so as构成以下两个句式做目的状语，功能同“to do”

（1）in order to+动词原形（可置于句首或句尾），意为“为了”。例如：

（2）so as to+动词原形（只能至于句末，不能置于句首）意为“为了”。例如：

John went to California in order to make a fortune.

2. 不定式作结果状语（通常出现在句尾,常用于固定搭配中：only to do; too…to do；so…as to do; such…as to do; …enough to do）

（1）表示出人意料或者不太好的结果时，用only to do.

 I hurried to the station, only to find the train had left.我匆匆赶到车站，结果发现火车已经开走了。

（2）“too …to …”结构常表示”太……而不能……”

He is too weak to do the work.他身体太弱，不能做这项工作。

注意：

①但 too 之前如果有only 时，则不定式表肯定。因为only too表示”非常;很”之意。

I’ll be only too pleased to help them out with any questions.我非常乐意为他们答疑解惑。

②too后如果是 happy, glad, pleased, satisfied, ready之类的形容词时，不定式也表示肯定意义。

She was too happy to meet her friend in the street.在街上遇到她的好朋友她很高兴。

（3）so +adj./adv.+as (not) to do 或such +n.+as (not) to do句型，表示“如此……以至于……”。例如：

The house is so high and narrow as to resemble a tower.这个房子又高又狭窄，像一座塔。

I’m such a fool as to think that she is a warm-hearted woman.我真傻，竟以为她是个热心肠的女人。

（4）adj./adv. + enough to do，意为“足以去做……”。例如：

The rooms are all large enough to take a third bed.这些房间都很大，足够放下第三张床。

3. 不定式作原因状语（一般不置于句首）：不定式的动作先于谓语动词，但很少用完成式。大部分表达情感等的原因。有以下3种句型：

（1）主语+be+表情绪或感情的形容词+不定式，用于这一结构的形容词主要有：afraid，angry，anxious，glad，happy，sorry，amazed，delighted，disappointed，excited，shocked，surprised。例如：

I am glad to see you.见到你很高兴。

We were very excited to hear the news.我们听到这个消息很兴奋。

（2）主语+表示情感的不及物动词+不定式。例如：

I couldn’t but laugh to hear such a funny story.听到这样一个有趣的故事，我忍不住笑了。

He smiled to think of a clever plan.想到一个聪明的计划，他笑了。

（3）主语+be+说明人的品质或行为的形容词+不定式。例如：

The boy was rude to speak to the teacher like that.那个男孩对老师那样说话很无礼。

The boy was clever to solve the problem so quickly.这个男孩这么快就解决了这个问题，真聪明。

注意：

不定式短语还可作独立成分，位于句首、句中或句末作状语。常见的短语有: to be exact(确切地说), to

begin with (首先)，to do him justice(说句对他公道的话), to be sure(诚然)，to be honest(实话说)。

Mindmap解析

习题-Exercises

一、完成句子

1．Jessie有了一个可以玩的新玩具。Jessie got a new toy __________________．

2．她没有可以依赖的朋友。She has no friend  __________________．

3．为了通过大学入学考试，我们必须努力学习。

____________________________________，we must work hard.

4．公共汽车停下来以便接载乘客。The bus stopped __________________________________．

5．令我们吃惊的是，这座寺庙仍保持着最初的样子。

We were astonished _________________ still in its original condition.

6．我匆忙赶到机场，结果发现John已经走了。

I rushed to the airport _________________ that John had gone.

二、单句语法填空

1．He liked nothing but __________ (watch) TV.

2．__________ (find) out more about the computer course，visit this website.

3. He is always the first __________ (come) to school.

4．__________ (tell) the truth, I am not happy at the moment.

5．The meeting__________ (hold) tomorrow is important.

6．We didn’t expect there __________ (be) so many people.

7．I tried to persuade him __________ (agree) to your proposal.

8．They don’t allow these books __________ (take)out of the reading room.

9．They did all they could __________ (save) the child.

10．I am glad __________ (work) with you now.

三、短文语法填空

Recently in the US，more students prefer 1.________(leave) the campus and study in a foreign country for half 2.________ one year.

Some people may be 3.________(frighten)：communicating in a foreign language，leaving friends and adjusting to a new environment are very difficult for students 4.________(study) abroad.However，the experience students have abroad is often impossible to gain at their home universities.

“Globally，there is so much 5.________(do)．I’m hoping 6.________(go) somewhere and experience something I wouldn’t get at home，”a student who intended 7.________(study) abroad said.

It was said that the increase had something to do with the universities’ promise that they encourage students to study overseas.The universities have been 8.________(real) good about saying that students need 9.________(go) abroad.

For many American students，some of the most important lessons abroad are those 10.________(experience) outside the classroom. Students can have deep opinions.Even very small cultural difference can surprise the students.

KEYS:

一、完成句子

1． to play with．

2．to depend on．

3．To pass the college entrance examination，we must work hard.

4．The bus stopped in order to/so as to pick up passengers．

5．We were astonished to find the temple still in its original condition.

6． I rushed to the airport，only to find that John had gone.

二、单句语法填空

1．He liked nothing but to watch(watch) TV.

2．To find(find) out more about the computer course，visit this website.

3. He is always the first to come (come) to school.

4．To tell(tell) the truth, I am not happy at the moment.

5．The meeting to be held(hold) tomorrow is important.

6．We didn’t expect there to be(be) so many people.

7．I tried to persuade him to agree(agree) to your proposal.

8．They don’t allow these books to be taken (take)out of the reading room.

9．They did all they could to save(save) the child.

10．I am glad to be working(work) with you now.

三、短文语法填空

1.to leave　2.or　3.frightened　4.to study　5.to do　6.to go　7.to study　8.really　9.to go　10.experienced