指不能单独作谓语的动词，同时保留了动词某些特征的动词形式，包括不定式，Ving和V-ed形式。
不定式（包括带to和不带to不定式）：
·及物动词的不定式有自己的宾语
I like to read books
·可以被状语修饰
He asked me to say my name aloud
·没有人称和数的变化
she liked to play the piano when she was young
·可用for/of sb表明它的逻辑主语
it's important for us to work hard
不定式的句法功能：
·作主语
To learn an art is very hard=> It is hard to learn an art.(it+be+形容词+不定式）
It is a great pleasure to work with you(it+be+名词+不定式)
·做表语
Our duty is to help the children to grow better
·作宾语（一般不直接作介词的宾语，若在介词后作宾语通常用“疑问词+不定式”结构，宾语后有补足语时，常用it作形式宾语而将不定式后置）
I really like to watch football
How I wish to see my old friends again！
i'm interested in what to do but not how to do it
We found it difficult to learn French well
常用不定式作宾语的动词有ask，wish，dare，offer，decide，help，arrange，learn，agree，refuse，hope，want，expect，promise，pretend，plan，manage，afford，prepare，long
·作补足语（有的动词需要用带to的不定式作宾语，有的则不需要比如使役动词have，make，let和感官动词feel，see，notice，watch，hear等）
I told jeff to join the club，but he wouldn't listen
These pictures made me think of my childhood
常用带to的不定式作宾语的动词有：teach，tell，get，ask，invite，force，want，warn，allow，require，cause，advise，order，encourage，permit，expect
·作定语（需放在被修饰词的后面）
Have you got anything to do this evening？（不定式和所修饰的
词之间动宾关系）
The next person to speak was a foreigner（被修饰词person是不定式的逻辑主语）
A pen to write with/a child to look after（不定式不及物，作定语要加必要的介词）
We are looking for a place to lie（in）（不定式修饰的名词是way，time，place等，可以省略介词）
·作状语（表目的，结果，原因或条件）
He came here to borrow my bike(目的状语）
He was too ill to travel（结果状语，不定式不能放句首）
I’m pleased to be invited to talk here(原因状语，不定式不能放句首）
·不定式的逻辑主语：
it's neceesary for us to get timely help around（不定式复合结构）
We think it impossible for such heavy work to be done within so short a time
注意：当形容词表示客观情况，描述不定式的特征，性质时，常用for引出不定式的逻辑主语，常用如easy，difficult，important，necessary，possible； 当形容词表主观情感或态度，常用of引出不定式的逻辑主语，常用有kind/nice/good，polite，rude，patient，careful，careless，wise，clever
·与疑问词连用的不定式（相当于名词，作主语，宾语，表语等）
How to get the information is a big problem.
The problem is which to choose.
·不带to的不定式
1，一些使役动词和感官动词（前面提到过）
2，Had better do sth最好做某事/cannot but do sth 情不自禁做某事/ do nothing but do sth只好做某事/have nothing to do but do sth只能做某事/can't help but do sth不得不做某事
·省略动词只保留to的不定式
I shall go if you wish me to（为避免重复）
V-ing形式：包括现在分词，动名词。
·作主语（动名词，表一种概念，习惯或经验，有时用it作形式主语把Ving放句尾）
Reading is an art（概念）
It is no use crying over spilt milk
·作宾语
1, 动名词，可跟在介词或某些动词后
Shall we have a rest or get down to doing our work？
i'm tired of having the same food every day
常跟Ving作宾语的常用动词advise，allow，avoid，miss，mind，delay，enjoy，finish，keep，practice，imagine，consider，cannot help，suggest，permit，risk
2, V-ing形式作宾语与不定式作宾语的区别（V-ing侧重习惯性动作，to do侧重具体的一次性动作）begin，start，hate，like，love，prefer后加Ving/to do意义几乎没有区别
I like playing football，especially to play with friends
She prefers living/to live abroad
有些动词后面+Ving和to do意义区别很大，比如：
Try doing试着做某事；try to do尽力做某事 | Regret doing后悔做过某事；regret to do遗憾地要做某事 | can't help doing禁不住...；can't help（to）do不能帮忙做... | Mean doing意味着；mean to do打算做... | Forget doing忘记做过某事；forget to do忘记做某事 | Go on doing继续做某事；go on to do继续做另外一件事 | Remember doing记得做过；rememer to do记着要做某事
·作补足语（是现在分词，表感官和心理状态see，hear，notice，watch，feel，smell，observe；使役动词have，get，leave，keep；以及find，catch后和宾语一起构成复合宾语，表示一个正在进行的动作）
I heard a girl crying not far away
Don't have your children working at their homework all the time
Often he found the girl quietly reading in the classroom
I heard a girl cry not far away（如感官动词后是“零不定式”则表示动作的全过程或经常性）
·作表语（动名词时：说明主语内容；现在分词时：说明事物的特点，性质等，已形容词化）
Your task is cleaning the windows
The speech you delivered is very interesting and encouraging
·作定语（动名词：被修饰词的某种用途，常置于被修饰词前；现在分词：表正在进行的动作；单个Ving作定语前置，Ving短语作定语后置）
A walking stick = a stick for walking拐杖
A sleeping child一个熟睡的孩子
·作状语（现在分词，修饰动词，表时间，原因，结果，条件，让步 ，行为方式，伴随等）
Hearing the exciting news，the boy jumped for joy（时间状语）
Living far from the company，I have to get up early every morning（原因状语）
The fire lasted nearly an hour，leaving nothing valuable（结果状语）
Working hard at your lessons，you are to succeed（条件状语）
Talking and laughing，the children walked one by one into the classroom（伴随状语）
V-ed形式
·做表语（基本形容词化，表主语某种性质或状态）
I turn around for my bag but it was gone
i'm so tired I could sleep for a week
·作定语（单个V-ed放被修饰名词前，表被动/完成；V-ed短语放在被修饰名词后，相当于一个定语从句）
They are cleaning the fallen leaves in the yard
Near the window，there is a bookshelf filled with many books（=that is filled with many books）
·作补足语（多来自及物动词，说明宾语的状态，性质或宾语承受某个动作，与宾语一起构成复合宾语，把带有宾语补足语的句子改为被动句，原来的宾语补足语变随之变为主语补足语）
Almost no student is seen punished in this school
I am going to have/get some letters mailed（自己寄/找人寄）
I had my bike broken on my way home（不愉快的只能用have不能用get）
·作状语（表时间，原因，让步，行为方式，伴随，条件等）
Told that his mother was ill，he hurried home quickly（时间状语）
Seriously injured，he had to be taken to hospital（原因状语）
Given more time and money，we would have done the work better（条件状语）
Followed by his dog，the hunter walked slowly in the forest（伴随状语）