第二部分 不定式

1. 不定式的三个结构：即否定结构、疑问结构和复合结构。 否定结构为―not (never) to do‖；

疑问结构是特殊疑问词―how (what, which, who, whether…) to do‖； 注明：(无if to do和why to do)

复合结构是―for/ of +名词（或代词宾格）+ to do ‖。

2. 不定式的三个时态形式和两个被动语态形式（可记忆为三时两语） 主 动 式 被 动 式 一般时to do /not to do to be done/not to be done 进行时to be doing /not to be 无 doing 完成时 to have done /not to have done to have been done /not to have been done 3. 动词不定式的功能

英语的句子成分有七种，即：主语，谓语，宾语，定语，状语，补足语，表语。动词不定式除去不能单独作谓语以外，其他六种成分均可充当。

（1）作宾语：

(1) 接不定式作宾语的系动词：appear，seem, prove, turn out, get……. (2) 接不定式作宾语的动词: 请牢记下列小诗：

决心学会想希望，拒绝设法愿假装。 主动答应选计划，同意请求帮一帮。

decide / determine, learn, want, expect / hope / wish, refuse, manage, care, pretend, offer, promise, choose, plan, agree, ask / beg, help

此外，afford, strive，demand，fail，happen，attempt 等也要用不定式作宾语。 （3）做形式宾语

结构：consider，judge，believe,make, feel, think, find +it +adj.+ to do sth Eg.I find it interesting to study history.

（2）.不定式用作定语的几种情况：

（1）.用来修饰被序数词、最高级或no, all, any 等限定的中心词。如： He was the best man to do the job.

Women and children were the first to get into the lifeboats. （2）用来修饰的词是抽象名词时，常见的有：ability, chance, idea, fact, excuse, promise, answer, reply, attempt, belief, way, reason, moment, time 等。如： Do you have the ability to read and write English ? I have to chance to go sight –seeing.

注意：1．作定语的不定式如果是不及物动词，或者不定式所修饰的名词或代词是不定式动作的地点、工具等，不定式后面须有相应的介词。如： The Browns have a comfortable house to live in. There is nothing to worry about. Please give me a knife to cut with. Here is some paper for you to write on. 但是，不定式所修饰的名词如果是time, place 或way时，不定式后面的介词习惯上省去。如：

He had no money and no place to live (in). We found a way to solve this problem (in). (3)目的和结果状语

不定式常用的句型：too…to do （太……而不能）, …enough to do…（够……就能……）, so as to do/in order to do（为了……）， so…as to do/such…as to do（如此……结果……）。 在这些常用句型中，注意so as to /in order to，前一个不能用于句首，而in order to既可放在句首，也可放在句尾。 so…as to与such…as to的区别是：

―so‖后一般接形容词或副词、可数名词单数（so + adj.+ a/ an + n.）。 ―such‖后一般接可数名词复数、不可数名词和可数名词单数形式（such + a/an + adj. + n.）。

so many/few+可数名词 除外 so much/little+不可数名词

一些常见的固定搭配的插入语： To tell you the truth To be frank/honest To be exact/specific To begin with

To make a long story short

4.let/make/have/see/hear/notice/observe/listen to/look at/watch/feel 这些动词带不定式作宾补时，省掉to, 若这些动词以被动形式出现时，应加上to。动词help后面作宾补的不定式可省略to，也可加to。例：I saw him go upstairs. 被动形式是: He was seen to go upstairs. 总结：它们是“吾看三室两厅一感觉‖——5看（look at, see, watch, notice, observe）；3使（make, let, have）；2听（listen to, hear）；1感觉（fell）。 注明：以上动词还可用现在分词作宾语补足语（5+3+2+1-2+4）：即以上动词除let, make 外都可以用现在分词作宾语补足语，此外find, catch, keep, lave 也可以用现在分词作宾语补足语。如：

At that time, I found him crying in the street. He was caught stealing.

I’m sorry to have kept you waiting for such a long time.

The missing boys were last seen playing near the river.

5. but/except + to do/ do 结构，要根据谓语动词来确定其后面的形式。当谓语动词是do, does, did时，but后用动词原形；谓语动词是其他动词时，but后用“to + 动词原形”的形式。

6. 不定式的逻辑主语要与主语保持一致

To study a foreign language, practice is needed. 这个句子逻辑主语不一致，应改为：To study a foreign language, one needs practice. 学习外语需要操练。 7. 形容词后一般用不定式（除busy, worth 两个外）例如： A) You are sure to succeed. （你一定能成功。）

B) I’m sorry to have given you a lot of trouble.（对不起，给你带来那么多麻烦。） C) He is busy preparing his lessons at present. （他现在正忙于预习功课。） 8. 不定式作定语和表语时，有时需要在后面放上一个适当的介词。 A) This is a bench to sit on.（这是用来坐的凳子。）

B) This room is comfortable to live in. （这个房间住起来很舒适。）

9. 在“主语+系动词+adj.+不定式”这个句型中，当主语是不定式的逻辑宾语时，不定式不用被动，不能在动词后再放宾语。例：

The question is easy to answer. （question是answer的宾语，不能说：The question is easy to be answered. 也不能说：The question is easy to answer it .） （二）不定式的相关句型：

(1)have no choice/alternative but to do …….

(2)have nothing to do but do /do nothing but /except do…….

(3)had better do /would rather do /would sooner do /can’t help but do /why not do (4)would like do ……..rather than do ……. (5) there is no need to do ……..

(6)it is said /known/reported/thought/considered/believed to do /be doing/have done (7)only to do /never to do

(8)can’t but do/can’t help but do/can’t choose but do

(9) consider，judge，believe, make, feel, think, find +it +adj.+ to do sth

(10)ability, chance, idea, fact, excuse, promise, answer, reply, attempt, belief, way, reason, moment, time ,wish to do

(11)be to blame, be to let 主动表被动

(12)was /were +to have done, would (should)like to have done

(13)intend ,mean,hope,plane,expect,want+to have done=had intended,meant,hoped……….to do表示按原来的计划，安排想要做，却没有发生的事。 三、不定式的主动和被动

1．不定式修饰的名词或代词和不定式逻辑上构成主谓关系时，不定式往往用主动形式。如： Do you have a knife to cut the watermelon ? (A knife cuts the watermelon.)

2．不定式和它前面被修饰的名词或代词构成逻辑上的动宾关系，又和该句主语构成逻辑上的主谓关系时，不定式常用主动形式。如：

She has a sister to look after. (She looks after her sister.) I know what to do. (I do what.)

3．不定式作表语形容词的关语，和句中主语构成逻辑上的动宾关系时，不定式多用主动形式，这是因为人们往往认为形容词后省去了for sb. 。如：

This book is difficult to understand. This kind of fish is nice to eat.

4．在there be 结构中，当说话人考虑的是必须有人去完成某件事时，不定式用主动形式；如果说话人强调的事情本身必须被完成，则用被动形式。如： There is a lot of work to do. (Someone has to do the work. ) There is a lot of work to be done. (The work has to be done. ) 请注意下面两个句子的含义的不同点：

There is nothing to do. (无事可做，感到十分乏味。)

There is nothing to be done. (某东西坏了，无法使之恢复正常。)