下面供參考。
動詞不定式是一種非謂語動詞形式,其結構為“to＋動詞原形”,其中to不是介詞,而是動詞不定式的符號,稱為小品詞,動詞不定式沒有人稱和數的變化.動詞不定式和其後面的名詞等構成不定式短語,在句子中可以用作主語、表語、賓語、補足語、定語、狀語等.
一. 作主語 例如：
To be a doctor is hard.
做醫生很難.
To learn English well is not easy.
學好英語不容易.
動詞不定式（短語）作主語時,為了避免句子的頭重腳輕,可以用“it”作形式主語,而把真正的主語－－動詞不定式（短語）放在句子的後部.例如上面的句子可以表示為：
It is hard to be a doctor.
It is not easy to learn English well. 再如：
It’s important to plant trees in spring.
如果動詞不定式的動作是誰做的,可以在動詞不定式前面加一個由介詞for引導的短語,稱為不定式的複合結構.例：
It’s good for us to read English aloud in the morning.
對我們來說每天早晨大聲讀英語是很有益的.
It is important for students to use English every day.
對學生來說每天使用英語是很重要的.
二. 作表語：
動詞不定式（短語）作表語常用於系詞be的後面.例：
His work is to drive a car.
他的工作是開車.
My job is to feed animals.
我的工作是飼養動物.
Her ambition is to be a doctor.
她的理想是當醫生.
三. 作賓語
動詞不定式（短語）可以放在一些動詞後面用作賓語,能以動詞不定式作賓語的動詞有：begin,start, want, forget, remember, show, learn, like, hate, love, ask等.例：
I want to tell you a story.
我想給你講個故事.
They begin to work at eight every morning.
他們每天早晨8點開始工作.
Don’t forget to lock the door.
別忘了鎖門.
Would you like to go and have a picnic with us tomorrow?
明天和我們一起去野餐好嗎?
*如果and連線兩個動詞不定式,第二個動詞不定式一般省“to”例：
（1）He wants to go and have a swim with us.
他想和我們一起去游泳.
（2）若作賓語的動詞不定式（短語）很長,可用it作形式賓語.
I find it interesting to learn English with you.
我覺得和你一起學英語很有趣.
He found it hard to catch up with others.
他覺得趕上別人很困難.
四. 作賓語補足語.例如：
The teacher asked us to read English for half an hour in the morning.
老師讓我們早晨讀半小時英語.
The teacher often tells Jim not to spend too much time playing computer games.
老師常告訴Jim不要花太多時間玩電腦遊戲.
Please let me help you.
讓我來幫助你.
動詞不定式作賓語補足語,表示賓語所做的動作,可以用動詞不定式作賓語補足語的動詞有：tell, ask, want, like, invite, encourage, help等.但在let, make, see, watch, hear, feel, notice, have等感官聽覺動詞或使役動詞後面作賓語補足語的動詞不定式一般要省略動詞不定式符號“to”,可以歸納為以下三種句式：
1.不可以省to的不定式作賓語補足語：
tell /ask / want / would like / wish / like / invite /encourage /teach sb. to do sth.
例：The teacher told us to come earlier tomorrow.
I want you to go now.
我想讓你現在就走.
Her parents wish her to be a teacher.
她父母親希望她當老師.
2.省“to”的不定式作賓語補足語：
Let / make / have sb. do sth.
Let the boy go out now.
讓那個男孩出去.
The boy made the baby cry.
男孩弄哭了這個小孩.
see / watch / hear / notice / feel sb. do sth.
I saw the students play basketball on the playground yesterday.
昨天我看見學生們在操場打籃球.
I often hear the girl sing in the next room.
我經常聽到女孩在隔壁唱歌.
3.可省可不省的：
help sb. （to）do sth.
I often help my mother （to）do housework.
我經常幫媽媽做家務.
*動詞不定式的否定式是直接在to之前加not. 例：
（1）Tell them not to play football in the street.
告訴他們不要在街道上踢足球.
（2）省to的動詞不定式的否定式是直接在動詞前面加not. 例：
Let the boy not go.
讓那個男孩別走.
（3）如果將主動語態變為被動語態時,作賓語補足語的動詞不定式變為主語補足語,動詞不定式則不省“to”,即原來省的再加上,例：
The baby was made to cry by the boy.
那個孩子被男孩弄哭了.
五. 動詞不定式作定語
動詞不定式作定語常用來修飾名詞或不定代詞,放於所修飾的詞後,為後置定語.例：
Who was the first one to arrive?
誰第一個到的?
She has no paper to write on?
她沒有紙寫字?
The best way to learn English is to use it.
學英語最好的方法是使用它.
When is the best time to plant vegetables?
什麼時候是種植蔬菜的最好時間?
Do you have something to drink?
你這有喝的嗎?
*動詞不定式（短語）作定語修飾名詞時,與其所修飾的詞具有一種動賓關係,如果不定式中的動詞為不及物動詞時,其後應加上一個含義上所需要的介詞.例：
I have no chair to sit on.
我沒有椅子坐.
He has no house to live in.
他沒有房子住.
六. 動詞不定式作目的狀語：
動詞不定式作目的狀語常用在go, come, hurry等不及物動詞後,表目的.
He went to see his sister yesterday.
他昨天去看妹妹了.
They got up early to catch the early bus.
他們早起去趕早班車.
有時可以把不定式（短語）提前,放於句首,表示強調目的.例：
To early English quickly and well, he went to England.
為了更快更好地學英語,他去了英國.
七. 不定式和疑問詞連用,可以作句子的主語、賓語、表語等.例：
The problem is where to get a computer. （表語）
No one knows how to do it.
沒有人知道如何做這件事.（賓）
I really don’t know which one to choose. （賓）
我真的不知道選哪一個.
When and where to have the party is not known. （主語）
何時何地舉行聯歡還不知道.
*不定式和疑問詞連用作賓語時有時可以改為賓語從句.例：
I don’t know what to do next.
我不知下一步該做什麼?
I don’t know what I should do next.
不定式用作獨立成分通常為一些固定短語,其中一個用法就是表總結：
To be brief, he was happy with the result. 簡言之,他對這個結果感到高興.
To conclude, I’d like to express my thanks to my family. 最後,我要感謝我的家人.
To conclude, I wish you all good health and a long life. 最後,祝大家健康長壽.
To cut a long story short, we said, ‘No!’ 長話短說吧,我們沒有同意.
To cut a long story short, he beat them one by one. 長話短說,他把他們一個個地打敗了.
To make a long story short, we agreed to disagree. 長話短說,我們同意各自保留不同的看法.
To sun up, most of the committee members supported the idea but a few were against it. 總之,大多數委員支援這一想法,但是也有幾個委員反對.
下面供參考。
動詞不定式是一種非謂語動詞形式,其結構為“to＋動詞原形”,其中to不是介詞,而是動詞不定式的符號,稱為小品詞,動詞不定式沒有人稱和數的變化.動詞不定式和其後面的名詞等構成不定式短語,在句子中可以用作主語、表語、賓語、補足語、定語、狀語等.
一. 作主語 例如：
To be a doctor is hard.
做醫生很難.
To learn English well is not easy.
學好英語不容易.
動詞不定式（短語）作主語時,為了避免句子的頭重腳輕,可以用“it”作形式主語,而把真正的主語－－動詞不定式（短語）放在句子的後部.例如上面的句子可以表示為：
It is hard to be a doctor.
It is not easy to learn English well. 再如：
It’s important to plant trees in spring.
如果動詞不定式的動作是誰做的,可以在動詞不定式前面加一個由介詞for引導的短語,稱為不定式的複合結構.例：
It’s good for us to read English aloud in the morning.
對我們來說每天早晨大聲讀英語是很有益的.
It is important for students to use English every day.
對學生來說每天使用英語是很重要的.
二. 作表語：
動詞不定式（短語）作表語常用於系詞be的後面.例：
His work is to drive a car.
他的工作是開車.
My job is to feed animals.
我的工作是飼養動物.
Her ambition is to be a doctor.
她的理想是當醫生.
三. 作賓語
動詞不定式（短語）可以放在一些動詞後面用作賓語,能以動詞不定式作賓語的動詞有：begin,start, want, forget, remember, show, learn, like, hate, love, ask等.例：
I want to tell you a story.
我想給你講個故事.
They begin to work at eight every morning.
他們每天早晨8點開始工作.
Don’t forget to lock the door.
別忘了鎖門.
Would you like to go and have a picnic with us tomorrow?
明天和我們一起去野餐好嗎?
*如果and連線兩個動詞不定式,第二個動詞不定式一般省“to”例：
（1）He wants to go and have a swim with us.
他想和我們一起去游泳.
（2）若作賓語的動詞不定式（短語）很長,可用it作形式賓語.
I find it interesting to learn English with you.
我覺得和你一起學英語很有趣.
He found it hard to catch up with others.
他覺得趕上別人很困難.
四. 作賓語補足語.例如：
The teacher asked us to read English for half an hour in the morning.
老師讓我們早晨讀半小時英語.
The teacher often tells Jim not to spend too much time playing computer games.
老師常告訴Jim不要花太多時間玩電腦遊戲.
Please let me help you.
讓我來幫助你.
動詞不定式作賓語補足語,表示賓語所做的動作,可以用動詞不定式作賓語補足語的動詞有：tell, ask, want, like, invite, encourage, help等.但在let, make, see, watch, hear, feel, notice, have等感官聽覺動詞或使役動詞後面作賓語補足語的動詞不定式一般要省略動詞不定式符號“to”,可以歸納為以下三種句式：
1.不可以省to的不定式作賓語補足語：
tell /ask / want / would like / wish / like / invite /encourage /teach sb. to do sth.
例：The teacher told us to come earlier tomorrow.
I want you to go now.
我想讓你現在就走.
Her parents wish her to be a teacher.
她父母親希望她當老師.
2.省“to”的不定式作賓語補足語：
Let / make / have sb. do sth.
Let the boy go out now.
讓那個男孩出去.
The boy made the baby cry.
男孩弄哭了這個小孩.
see / watch / hear / notice / feel sb. do sth.
I saw the students play basketball on the playground yesterday.
昨天我看見學生們在操場打籃球.
I often hear the girl sing in the next room.
我經常聽到女孩在隔壁唱歌.
3.可省可不省的：
help sb. （to）do sth.
I often help my mother （to）do housework.
我經常幫媽媽做家務.
*動詞不定式的否定式是直接在to之前加not. 例：
（1）Tell them not to play football in the street.
告訴他們不要在街道上踢足球.
（2）省to的動詞不定式的否定式是直接在動詞前面加not. 例：
Let the boy not go.
讓那個男孩別走.
（3）如果將主動語態變為被動語態時,作賓語補足語的動詞不定式變為主語補足語,動詞不定式則不省“to”,即原來省的再加上,例：
The boy made the baby cry.
The baby was made to cry by the boy.
那個孩子被男孩弄哭了.
五. 動詞不定式作定語
動詞不定式作定語常用來修飾名詞或不定代詞,放於所修飾的詞後,為後置定語.例：
Who was the first one to arrive?
誰第一個到的?
She has no paper to write on?
她沒有紙寫字?
The best way to learn English is to use it.
學英語最好的方法是使用它.
When is the best time to plant vegetables?
什麼時候是種植蔬菜的最好時間?
Do you have something to drink?
你這有喝的嗎?
*動詞不定式（短語）作定語修飾名詞時,與其所修飾的詞具有一種動賓關係,如果不定式中的動詞為不及物動詞時,其後應加上一個含義上所需要的介詞.例：
I have no chair to sit on.
我沒有椅子坐.
He has no house to live in.
他沒有房子住.
六. 動詞不定式作目的狀語：
動詞不定式作目的狀語常用在go, come, hurry等不及物動詞後,表目的.
He went to see his sister yesterday.
他昨天去看妹妹了.
They got up early to catch the early bus.
他們早起去趕早班車.
有時可以把不定式（短語）提前,放於句首,表示強調目的.例：
To early English quickly and well, he went to England.
為了更快更好地學英語,他去了英國.
七. 不定式和疑問詞連用,可以作句子的主語、賓語、表語等.例：
The problem is where to get a computer. （表語）
No one knows how to do it.
沒有人知道如何做這件事.（賓）
I really don’t know which one to choose. （賓）
我真的不知道選哪一個.
When and where to have the party is not known. （主語）
何時何地舉行聯歡還不知道.
*不定式和疑問詞連用作賓語時有時可以改為賓語從句.例：
I don’t know what to do next.
我不知下一步該做什麼?
I don’t know what I should do next.
不定式用作獨立成分通常為一些固定短語,其中一個用法就是表總結：
To be brief, he was happy with the result. 簡言之,他對這個結果感到高興.
To conclude, I’d like to express my thanks to my family. 最後,我要感謝我的家人.
To conclude, I wish you all good health and a long life. 最後,祝大家健康長壽.
To cut a long story short, we said, ‘No!’ 長話短說吧,我們沒有同意.
To cut a long story short, he beat them one by one. 長話短說,他把他們一個個地打敗了.
To make a long story short, we agreed to disagree. 長話短說,我們同意各自保留不同的看法.
To sun up, most of the committee members supported the idea but a few were against it. 總之,大多數委員支援這一想法,但是也有幾個委員反對.