1. 作主語：The cat said, “To take roller coaster” is terrible.
不定式短語作主語時，可以直接放在句首，但在很多情況下，尤其是在疑問句和感嘆句中，往往放在謂語之后，而用先行代詞it作形式主語。
→ The cat said, “It’s terrible to take roller coaster.”
How long did it take you to take roller coaster?
How terrible it is to take roller coaster?
不定式作主語常見句型：
a) It is + adj. (easy, important, difficult…) + 不定式
b) It is + n. (a pity, a pleasure, one’s duty, a shame) + 不定式
eg. It’s my duty to teach you how to be a student of No.3 Middle School.
c) It takes/needs/requires + some time (hours, months, days, patience…) + 不定式
eg. It requires patience to be a good teacher.
2. 作表語：當句子的主語是aim, idea, policy, question, suggestion, wish, task, duty, job, purpose等或者主語是what引導的名詞性從句時，后面可以用不定式做表語，用以說明主語所包含內容。
eg. Our most important task now is to make a plan.
注：作表語的不定式都帶to，但當主語部分有實義動詞do時，to可以省略。
eg. The only thing we can do now is wait and see.
3.作賓語
The cat said “Remember not to take it next time!”.
a) 可以直接用不定式作賓語的動詞很多，常見的有：agree, afford, tend, ask, decide, determine, expect, fail, hope, learn, intend, manage, offer, plan, promise, refuse, want, wish等
2005年天津卷12題：I don’t want _____ like I’m speaking ill of anybody, but the manager’s plan is unfair.
A. to sound B. to be sounded C. sounding D. to have sounded
當不定式短語比賓補長時，往往將不定式放到賓補后，而用先行代詞it作形式賓語，常用動詞有feel, think, find, believe, consider, make等。
The cat felt it terrible to take roller coaster.
b) 不定式一般不作介詞的賓語，只有少數介詞如but, except等后面可以跟不定式作賓語。一般情況下作介詞賓語的不定式都帶to，如果but或except所在句子里的謂語動詞都是實義動詞do, does, did時，通常省略to。
Eg. We have no choice but to wait.
Cf. We can do nothing but wait.
4. 賓語補足語
在SVOC句型中，許多動詞都可以按不定式作賓語補足語。
a) 通常作賓語補語的不定式要帶to，常用于以下動詞之后：ask, tell, advise, allow, enable, expect, force, get, like, order, teach, want, invite, wish, beg等
You should get them to help you.
但在謂語動詞believe, find, think, feel, consider, suppose, imagine, prove等后面跟to be…作賓補，不跟to do…
eg. They believe him to be honest.
b) 以下兩類動詞后跟不定式作賓補時不能帶to
①一些表示“致使”意義的動詞，如：let, have, make等
②一些表示感覺的動詞，如：hear, feel, see, watch, notice等
Don’t let the children trouble you.
I heard someone open the door.
但當這兩類動詞為被動態時，不定式就成了主補。作主補的不定式必須加上to
His father made him go to bed early.
→He was made to go to bed early by his father.
5. 作定語
不定式可以在句子充當后置定語，修飾名詞。
以下幾類情況常用不定式作定語：
①能帶不定式作賓語的動詞，其同源名詞可以帶不定式作定語。常見的有attempt, decision, promise, plan等
eg. He hasn’t kept his promise to write to his parents regularly.
②常與不定式搭配的形容詞，其同源名詞一般可以用不定式作定語。常見的有ability, determination, anxiety, eagerness等
eg. His eagerness to finish his homework was quite clear.
③序數詞形容詞最高級或被only, last, next等修飾的名詞可以用不定式作定語：
She was the only person to survive after the earthquake.
Tips: 不定式在作定語時，有時與被修飾的名詞有意義上的主謂關系、同位關系、動賓關系，如果該不定式是不及物動詞，它后面需要加上適當介詞。
Eg. He’s always the first to come and the last to leave. 主謂關系
I’ve no time to listen to your excuse. 同位關系
She has a meeting to attend. （動賓關系=attend a meeting）
There’s nothing to worry about. (動賓關系=worry about nothing)
6. 作狀語
不定式可以作狀語，表示目的、結果、原因、條件等。
①to…, in order to …, so as to …(不能放在句首)作目的狀語
2005年遼寧卷22題：All these gifts must be mailed immediately _____ in time for Christmas.
A. in order to have received B. in order to receive C. so as to be received D. so as to be receiving
②在so…as to, such….as to, only to …結構中不定式作結果狀語，其中only to…用于表示意想不到的結果。
He hurried to the station only to find the train had gone.
③enough to, too…to結構
eg. The boy isn’t old enough to go to school.
= The boy is too young to go to school.
④形容詞（happy, glad, lucky, fortunate, surprised, angry, anxious, ready, quick, slow, cruel, clever等）+ 不定式結構
eg. I’m glad to meet you.
The question is different to answer.
He is hard to get along with.
7. 作插入語，用來說明說話人的態度、看法、對整個句子進行解釋，如to be frank（坦白地說），to be sure（確實）等。
Eg. To tell you the truth, I hate you.
8. 作同位語
eg. The order to start the general attack soon came.
不定式的復合結構，以it為形式主語或形式賓語引導的復合結構，如果其前的形容詞是指行為的性質就用：for sb. to do sth.這種復合結構在句中可作主語、表語、賓語、定語、狀語等。
It is necessary for me to learn English well.
如果該形容詞是指行為的性質，同時又指行為的人，則用of sb. to do sth.。這種句式中的常用形容詞有：right, wrong, brave, careful, careless, clever, wise, stupid, cruel, foolish, good, honest, kind, nice, silly等。
eg. It’s very kind of you to come to see me.
連接代（副）詞+不定式（包括whether, what, which, whom, where, when, how, 不包括why），在句中起名詞的作用，通常跟在諸如tell, know, show, decide, learn, wonder, explain等動詞后作賓、主語或表語。
Eg. No one can tell me where to find John.
When to the exam is still unknown.
The problem is how to get enough money.
不定式的進行式、完成式和被動式
①不定式的進行式由to be + V-ing構成，用來表示謂語動詞動作發生時，不定式的動作正在進行。
Eg. Some students pretended to be reading English when the teacher came in.
②不定式完成式由to have + V-ed構成，用來表示動作發生在謂語動作之前。
Eg. 2005年江蘇卷No.25
--- Is Bob still performing?
--- I’m afraid not. He is said _______ the stage already as he has become an official.
A. to have left B. to leave C. to have been D. to be left
答案是A
③不定式的被動式分為一般式被動to be V-ing和完成式被動to have been V-ed。當不定式的邏輯主語是不定式所表示的動作的承受者時，不定式要用被動語態。
Eg. It is an honour for me to be invited to the party.
The book is said to have been translated into many languages.
2005年遼寧卷No.22
All these gifts must be mailed immediately _____ in time for Christmas.
A. in order to have received B. in order to receive C. so as to be received D. so as to be receiving
動名詞
1. 動名詞的句法功能：動名詞由動詞加ing構成，與現在分詞的形式相同。動名詞主要起名詞作用，在句中擔任主語、表語、賓語和定語。
①作主語，可以直接放在句首，也可以用先行代詞it作為形式主語，而把動名詞后置。
eg. Seeing is believing. (眼見為實)
Saying is easier than doing.
Collecting stamps is a good hobby. (單個動名詞短語作主語時，動詞用單數)
動名詞作主語還有以下兩個習慣表答法：
It is no use (good) + 動名詞：做某事沒有用
Eg. It’s no use crying over spilt milk. (覆水難收)
There is no + 動名詞 (= It is impossible to do sth.)
Eg. There is no knowing what may happen.（未來的事無法知道）
②作表語：通常是說明主語的內容，注意它與謂語動詞進行時的區別
eg. His hobby is collecting stamps. (此句為SVC結構) 可改為：Collecting stamps is his hobby.
Cf. He is collecting stamps. (is collecting是謂語動詞進行時，此句為SVO結構)
不能改為：Collecting stamps is he.
③作賓語
A. 作及物動詞 的賓語(enjoy, mind, finish, appreciate, avoid, consider, delay, escape, pratise, suggest, keep(on), miss)
eg. 2005年上海卷No.32
He got well-prepared for the job interview, for he couldn’t risk _____ the good opportunity.
A. to lose B. losing C. to be lost D. being lost
答案為B
有些動詞（attempt, begin, continue, hate, like, love）后面既可以接不定式作賓語，也可以接動名詞作賓語，意義差別不大。通常認為用動名詞泛指一般的傾向性，用不定式則表示特定或具體某一種動作。
Eg. I like swimming but I don’t like to swim in winter.
動詞prefer后面接不定式作賓語時，句子結構與按動名詞作賓語是不一樣。
eg. I prefer to drive rather than to be driven.
I prefer driving to riding.
有些動詞，如forget, remember, regret等，后面接動名詞表示的動作先于謂語動詞動作，不定式表示的動作后于謂語動詞。
Eg. 2005年北京卷No.30
When asked by police, he said that he remembered _____ at he party, but not ______.
A. to arrive, leaving B. to arrive, to leave C. arriving, leaving D. arriving, to leave
在下列句型中動名詞作真正賓語：
動詞+it（形式賓語）+賓補+動名詞（真正賓語）
eg. I think it no use telling them.
We think it no good inviting to him.
B. 作介詞的賓語
Eg. 2005年浙江卷No.3
The president spoke at the business meeting for nearly an hour ______ his notes.
A. bringing up B. referring to C. looking for D. trying on
be used to doing 習慣于做；look forward to doing 盼望做；devote one’s life to doing 致力于做；spent time (in) doing 花時間做；be fond of doing 喜愛做；be good at doing 擅長做；be proud of doing 為做…而自豪；be tired of doing 對做…感到厭倦；feel like doing 欲想做； go on doing 繼續做（原來的事）；keep on doing 不停地做；what about doing 做…怎么樣；think of doing 考慮做；be interested in doing 對做…感興趣；have some difficulty/trouble (in) doing 做某事有困難；be busy (in) doing 忙于做；instead of doing 做…而不做…
eg. 2005年江蘇卷No.23
Everybody in the village likes Jack because he is good at telling and ______ jokes.
A. turning up B. putting up C. making up D. showing up
答案為C
④作定語
動名詞可作前置定語，表示所修飾的詞的用途或目的，可用for改寫；而現在分詞作定語時，可用定語從句改寫。
swimming pool waiting room walking stick
a sleeping car=a car for sleeping a sleeping child= a child who is sleeping
⑤作同位語
eg. That’s the queen’s full-time job, laying eggs. 這就是蟻后的專職工作??產卵。
2．動名詞的邏輯主語
①人稱代詞做邏輯主語時應用所有格，即形容詞性物主代詞。
Eg. Do you minding my smoking here?
②邏輯主語是不定代詞或指示代詞時，很少用所有格，而用普通格。
Eg. He was awakened by someone knocking the door.
There’s no need for that being done.
③邏輯主語是名詞時，用所有格，但是如果名詞為無生命物體時，則用普通格。
Eg. Mary’s laughing made Tom angry.
There is no hoping of the factory making profit.
④在口語中，動名詞如果不在句首，可以用名詞普通格或人稱代詞賓格作邏輯主語。
Eg. 2005年安徽卷No.34
I really can’t understand _____ her like that.
A. you treat B. you to treat C. why treat D. you treating
3. 動名詞的完成式、一般式被動和完成式被動。
Eg. After having finish his work, he went home.
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