不定式构成

基本构成：to + 动词原形 (to do)
否定式：not to + 动词原形（not to do）

I have a lot of work to do.

不定式 to 只是符号，本身没有意义，不要和介词to 搞混

She’s never been to Paris.

不定式英文infinitive，不限定，无限制
在句子中充当成分基本不受限，能充当除了谓语之外的任何句子成分。
包括：主语、表语、宾语、宾补、定语和状语。

不定式作主语

1. 不定式 to do 在句首的主语位置

To know yourself is the beginning of all wisdom.
To err is human.

不定式作主语 VS 动名词作主语

很多情况下可以用动名词替换

yaml

= Knowing yourself is the beginning of all wisdom.

谚语，俗语，通常不用动名词替换，不说Erring is human.

2. 不定式 to do 后置，用 it 作形式主语

It is + 形容词 + to do

如difficult, easy, hard, important, impossible, necessary

It is + 名词 + to do

如It is a shame/ a virtue/ one’s responsibility/ one’s horror to do 等

It takes sb sth to do

如 It takes sb some time to do / It takes sb some money to do 等

It’s hard to restore broken trust.
It’s my honor to be here.
It takes tow to tango.

不定式作表语

表示目的，事态发展的结果、预期的结果

To live is to suffer.
To survive is to find some meaning in the suffering.

不定式作宾语

常见接不定式作宾语的动词：

decide, choose, hope, expect, refuse, promise, fail, manage, plan, prepare, learn, hate, like, prefer

I hope to see you soon.
She promised to help.

动词后面接不定式 or 动名词？

  1. 有的动词后面只能接动名词：consider, enjoy, avoid, finish等
  2. 有的动词后面只能接不定式：decide, hope, fail, refuse等
  3. 有的两者皆可；含义差别不大：begin, start, continue等
  4. 有的两者意义不同：remember to do / remember doing（记得去做 / 记得做过）

疑问词 + to do 作动词宾语

前面搭配what, who, where, how

I don’t know what to say.
She hasn’t decided where to go next.

不定式作宾补

表示指示、愿望或感受的动词可以构成“动词 + 宾语 + 不定式（作宾补）”

advise, persuade, instruct, allow, permit, remind, order, force, ask, tell, wish, want, expect, let, make, have, see, hear, feel, watch

Singapore advises unvaccinated people to stay home as cases rise.
I’m gonna ask Monica to marry me.

如果动词是使役动词let, make, have
或者感官动词 see, hear, feel, watch, notice 等，
此时作宾补不定式要省略不定式符号to

I heared them to quarrel last night.

不定式作定语

放在所修饰的名词或代词后面，可以与其修饰词构成主谓关系或动宾关系

I have a lot of work to do. (do the work -> 动宾)
He is the best person to do this job. (person do this job -> 主谓)

不定式作状语

“招牌”功能是表目的。除此外，还可以作结果状语和原因状语

Eat to live, not live to eat.（表目的）
What have I done to make you so angry?（表结果）
I’m glad to see you look so well.（表原因）

不定式逻辑主语：for sb / of sb

It is necessary to learn some grammar rules.
It is necessary (for us) to learn some grammar rules.

It is + 形容词 + of sb to do.
形容词表示“人的品质特征或行为表现”
brave, careful, careless, clever, wise, generous, kind, nice, polite, rude, silly, considerate

It was careless of me to leave the door open.

for sb 用来描述事情的性质
of sb 用来描述人的性质

It is common for children to be afraid of the dark.

不定式的时态和语态

主动语态 被动语态
一般式 to write to be written
进行式 to be writing ——
完成式 to have written to have been written
完成进行式 to have been writing ——

不定式的时态：一般式 to do

表示的动作与谓语动词的动作同时发生或者在其后发生

She bought a bookshelf to put her books on. （之后）
He’s learning to play the guitar. (同时)

不定式的时态：进行式 to be doing

表示的动作与谓语动词的动作同时发生而且正在进行

He pretended to be sleeping when his girlfriend walked in.
You tow seem to be getting along.

不定式的时态：完成式 to have done

表示动作先于谓语动词的动作发生，经常用于表示态度
情感（如 be sorry / happy / lucky to have done）
观点（如 be believed / thought / considered to have done ）
推断（如 seem / appear to have done ）的谓语动词后

I’m sorry to have kept you waiting.
I seem to have seen her somewhere.

还用于表意图、计划、打算
如 expect, hope, intend, mean, plan
表示本打算做，但是事实上没有实现的动作

He intended to see me off at the airport. (描述计划，结果未知)
He intended to have seen me off at the airport. (本打算做，没有实现)

不定式的时态： 完成进行式 to have been doing

动作在谓语动词的动作之前发生，且一直进行着

She seems to have been waiting for someone all day.

不定式语态

如果句子中出现了不定式动作的执行者，则不定式用主动语态；
如果没有出现执行者，或者不定式所修饰的成分是不定式动作的承受者，用被动语态。

I have a lot of clothes to wash. （洗衣服的人是我）
I have a lot of clothes to be washed. （别人洗）

在特定结构中，也会出现不定式主动语态表被动情况
如“ sth be + 形容词 + 不定式 ” 句型

This movie is interesting (for us/people) to watch.
Spaghetti is easy (for us/people) to cook.

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