[高中]全新語法:動詞不定式 三、動詞不定式的句法作用
三、動詞不定式的句法作用
1.作主語
（1）不定式在句子中可以作主語，謂語動詞用單數。
To study hard is necessary.努力學習是有必要的。
To get up early is a good habit.早起是個好習慣。
（2）不定式作主語的句子變被動語態(tài)時，必須用形式主語。
It was decided to set up a new football club in our school.
已經決定在我們學校建立一個新的足球俱樂部。
It is wanted to make big money by most people.許多人都想掙大錢。
（3）形式主語：常用it來作形式主語，代替不定式或不定式短語。
It is+名詞+to do sth.做……是……
It is+形容詞+to do sth.做……是……
It is+形容詞+for sb.to do sth.對某人來說，做……是……
It is+形容詞+of sb.to do sth.某人做…… 是……
It’s like sb.to do sth.像某人做某事的風格
It seems/appears+形容詞+to do sth.做……看起來……
It takes sb.some time to do sth.做……花了某人多少時間
It’s up to sb.to do sth.由……決定
It is our duty to serve the people.
為人民服務是我們的責任。（真正主語to serve ...）
It is not easy to learn a foreign language.
學會一門外語是不容易的。（真正主語to learn ...）
It is difficult to do the job.做那項工作很困難。（真正主語to do ...）
It’s very necessary for us to practise listening and speaking.
我們很有必要練習聽和說。（真正主語for us to practice ...）
It is so nice of you to come to see me.
你來看我太好了。（真正主語of you to come ...）
It’s like him to leave the work to others.（真正主語to leave ...）
他就是這樣的一個人，總是把工作推給別人。
It seems good to have a drink now.
現在喝點什么倒還不錯。（真正主語to have ...）
It took more than 100，000 slaves twenty years to build the Great Pyramid.
十萬多個奴隸花了20年的時間建成了那座大金字塔。（真正主語to build ...）
It is up to parents to teach their children manners.
該由父母教孩子禮貌。（真正主語to teach ...）
2.作表語
（1）表示目的打算及具體內容。
His wish was to become a skilful worker.他的愿望是要成為一名技術熟練的工人。
What he hoped was to be admitted into the university.他的希望就是能被大學錄取。
（2）不定式被動形式作表語，相當于can/could，should，ought to，must等意義。
You are to be rewarded.你應該受到獎勵。（should）
It’s nowhere to be found.哪兒也找不到它。（can’t be）
These books are not to be sold.這些書不應該賣掉。（ought not to be）
（3）表示“同意、安排、命令、決定、勸告、意愿、禁止”等。
They are to marry next week.他們將在下周結婚。（安排）
Children are not to smoke.兒童不準吸煙。（禁止）
You must be persistent if you are to succeed.想要成功，就必須有毅力。（愿望）
（4）seem，appear，prove，turn out等后接to be不定式時，可省略to be。
He seems （to be）ill.他似乎生病了。
The man turned out （to be）an cheater.這人竟是個騙子。
She proved （to be）a very strict teacher.她被證明是一位非常嚴格的老師。
He appeared （to be）about fifty years of age.他看起來大約50歲。
【提示】 主語中含有do的某種形式時，作表語的不定式可省略to。
What he wanted to do was （to）help the old man.他想做的是要幫一下這個老人。
3.作賓語
（1）作及物動詞的賓語
常用不定式作賓語的動詞：
afford 負擔起 agree 同意 arrange 安排 attempt 打算
ask 要求 care 想要 choose 選擇 dare 敢于
decide 決定 demand 要求 determine 決心 expect 期待
fail 未能 hesitate 猶豫 hope 希望 intend 想要
learn 學習 long 渴望 manage 設法 offer 主動
plan 計劃 prepare 準備 pretend 假裝 promise 答應
refuse 拒絕 seek 試圖 want 想要 wish 希望
We have decided not to go.我們決定不去了。
He has promised to get me a position.他答應給我安排一個職位。
We have decided to experiment with a new method.我們決定用新方法進行試驗。
We want to hear all about his adventure.我們想知道他奇遇的一切情況。
（2）“疑問詞+不定式”作動詞賓語
I don’t know what to do next.我不知道下一步該做什么。
I asked how to solve the problem.我問如何解決這一問題。
He forgot where to buy such a book.他忘了去哪兒買這樣一本書。
He has to learn how to collect water，hunt for food，and make fire.
他得學會收集淡水、尋找食物、生火什么的。
（3）作介詞的賓語
I have no idea of who to do it.我不知道誰去做此事。
They were concerned with what to deal with the problem.
他們關心的是如何解決問題。
Your success will largely depend upon how to do it.
你成功與否將主要取決于你怎樣做。
They are discussing about where to give the lecture.他們正在討論在哪里舉行講座。
【提示】 介詞的賓語主要由“疑問詞+不定式”短語充當。
4.作賓語補足語
（1）不省略to的動詞不定式作賓語補足語
常用“vt.+sb.to do sth.” 句式的動詞：
advise 勸告 allow 允許 ask 請求 bear 容忍
beg 乞求 cause 導致 command 命令 direct 指導
drive 驅使 elect 推舉 enable 使某人能夠 encourage 鼓勵
expect 期望 forbid 禁止 force 強迫 get 讓某人去
hate 討厭 help 幫助 intend 打算 invite 邀請
like 喜歡 mean 打算 need 需要 oblige 迫使
order 命令 permit 允許 persuade 說服 prefer 寧愿
recommend 推薦 remind 提醒 request 要求 require 要求
teach 教育 tell 告訴 train 訓練 trouble 麻煩
want 想要 warn 警告 wish 希望
The teacher asked us to finish our homework.老師叫我們完成家庭作業(yè)。
She wanted him to sing for her friends.她想讓他為她的朋友唱歌。
The policeman told the boys not to play in the street.警察告訴孩子們別在街上玩耍。
Please remind me to post this letter.請?zhí)嵝盐壹倪@封信。
【比較】
①I don’t allow/permit him to swim.我不允許他游泳。（不定式作賓補）
I don’t allow/permit swimming here.我不許在此地游泳。（動名詞作賓語）
②I advise you to take medicine.我建議你吃藥。（不定式作賓補）
I advise taking medicine.我建議吃藥。（動名詞作賓語）
（2）“to be不定式”作賓語補足語
常用“vt.+sb.+to be ...”句式的動詞：
acknowledge 承認 believe 相信 consider 認為 declare 宣稱
discover 發(fā)現 feel 感覺 find 找到 guess 猜想
imagine 想象 judge 判斷 know 知道 prove 證明
suppose 猜想 take 以為 think 認為 understand 了解
I consider him to be the cleverest.我認為他是最聰明的。
We discovered him to be a cheat.我們發(fā)現他是一個騙子。
I find English to be very easy.我發(fā)現英語很容易。
I supposed him to be away from home.我想他不在家。
【提示】
①這類句式后的不定式用進行式或完成式時，to be不能省略。
They believe him to be writing a new book.他們認為他正在寫一本新書。
I consider the work to have been finished.我估計活已干完了。
②這類句式的被動結構為“主語+is done+to do/be doing/have done”。
The film is believed to be the best this year.這部電影被認為是今年最好的。
He is believed to be writing a new book.人們認為他正在寫一本新書。
They are supposed to have finished.他們應該完成了。
③作短語動詞后的賓語補足語
appeal to sb.to do sth.呼吁某人做某事 arrange for sb.to do sth.安排某人做某事
call on sb.to do sth.號召某人做某事 care for sb.to do sth.愿意某人做某事
count on sb.to do sth.指望某人做某事 depend on sb.to do sth.依靠某人做某事
long for sb.to do sth.盼望某人做某事 rely on sb.to do sth.依靠某人做某事
wait for sb.to do sth.等待某人做某事 would like sb.to do sth.希望某人去做某事
The government is appealing to everyone to save water.政府呼吁人人節(jié)約用水。
The crocodile waited for the monkey to come down again.鱷魚等著猴子再下來。
The chairman called on Mr Brown to speak.主席請布朗先生講話。
（4）省略to的不定式作賓語補足語
see 看到 watch 觀看 notice 注意 observe 觀察 look at 看著
hear 聽到 listen to 聽著 feel 感覺 make 使 let 讓 have 使
You must watch me carefully do everything.你必須仔細觀察我所做的一切。
I often hear him sing this song.我經常聽到他唱這首歌。
I felt someone open my door.我感覺有人開了我的門。
It will make the cabbage grow big and strong.它將使白菜長得又大又壯。
【提示】 這類句式變?yōu)楸粍诱Z態(tài)時，不定式符號to 要補出。
He was seen to write a letter.有人看見他寫了一封信。
（5）it作形式賓語
They found it impossible to get everything ready in time.
他們發(fā)現不可能把一切按時準備好。（真正賓語to get ...）
She thought it unnecessary to argue with him.
她覺得沒有必要和他辯論。（真正賓語to argue ...）
Do you consider it better not to go？ 你覺得不去更好嗎？（真正賓語not to go）
5.作定語
（1）主謂關系
He was the best man to do the job.他是做這工作的最佳人選。
Gina is the first to know my e-mail address.吉娜是第一個知道我電郵地址的。
You are the right person to do the job.你是做這項工作合適的人選。
She was the only one to survive in the air crash.她是空難中唯一幸存的人。
【提示】 the last ...to do sth.意為“最不可能的……”。
He is the last man I want to see.他是我最不想見的人。
She is the last woman in the world to be a farmer’s wife.她最不適宜作農夫的妻子。
（2）動賓關系
I have many letters to write.我有許多信要寫。
I have some clothes to wash.我有一些衣服要洗。
It was a game to remember.那是一場令人難忘的球賽。
【提示】
①在“動賓關系”中，不定式作定語要用及物動詞的主動形式。
I have a lot of work to do today.我今天有很多工作要（自己）做。
②如果動詞是不及物動詞，其后要加必要的介詞。
Give me a pen to write with.給我一只鋼筆寫字用。
Maria is a pleasant person to work with.和瑪麗亞一起工作真愉快。
He has no house to live in.他沒有房子住。
I have enough money to buy the book with.我有足夠的錢買這本書。
I lit a candle to read by.我點起蠟燭來看書。
（3）偏正關系：不定式常用于某些名詞后作定語。
ability 能力 ambition 志向 anxiety 焦慮 attempt 企圖
campaign 運動 chance 機會 courage 勇氣 decision 決定
desire 欲望 determination 決心 effort 努力 failure 失敗
refusal 拒絕 promise 許諾 tendency 趨勢
I had a dream to fly in the sky like a bird.我做了一個像鳥兒一樣在天上飛的夢。
I have a wish to go to college.我有一個上大學的愿望。
They made a plan to study English.他們制訂了一個學習英語的計劃。
Everyone has the right to speak at the meeting.人人都有在會議上講話的權利。
【提示】
①在idea，habit，method，purpose等詞后只用“of doing ...”作定語。
They got the happy idea of climbing the hill.他們想到爬山的好主意。
I am in the habit of rising early.我習慣早起。
②在way，pleasure，time，chance，opportunity，plan，power等詞后可用“to do sth.或of doing sth.”作定語。
Do you know the way of mastering English？ 你知道精通英語之道嗎？
Do you know the way to master English？
【比較】
①She was on her way to catch the school bus.
她在趕搭校車的途中。（on one’s way to do ...）
②He is on his way to becoming a journalist.
他將會成為一名新聞記者。（on one’s way to do ...）
6.作狀語
（1）作目的狀語
We started early to avoid being late.我們一早就動身免得遲到。
I came to hear the report.我是來聽報告的。
【辨析】我一早動身以便及時到達那里。
【正】To get there in time I started early.（to do置于句首，作目的狀語）
【正】I started early to get there in time.（to do置于句末，作目的狀語）
【正】In order to get there in time I started early.（in order to目的狀語，置于句首）
【正】I started early in order to get there in time.（in order to目的狀語，置于句末）
【正】I started early in order that I could get there in time.（in order that引導目的狀語從句）
【誤】So as to get there in time I started early.（so as to 目的狀語不能置于句首）
【正】I started early so as to get there in time.（so as to 目的狀語只能置于句末）
【正】I started early so that I could get there in time.（so that引導目的狀語從句）
（2）作結果狀語
He grew up to be a famous scholar.他長大以后成了有名的學者。
I opened the door to find the room empty.我打開門，結果發(fā)現房間是空的。
He woke up to find everyone gone.他醒來發(fā)現人都走了。
不定式作結果狀語的常用句式：
（1）“only to do ...”表示“出乎意料的結果”；
（2）“never to do ...” 表示“再也沒有……的結果”；
（3）“such/so ...as to do ...”表示“如此……以至于”；
（4）“adj./adv.+enough to do ...”表示“足以……”；
（5）“too ...to do ...”通常表示否定意義，意為“太……以致不能”。
He worked hard only to fail.他努力工作結果卻只有失敗。
They parted，never to see each other again.他們分手了，從此沒有再見面。
He isn’t old enough to join the army.他還不到參軍的年齡。
He runs fast enough to catch the bus.他跑得夠快，足以趕上公共汽車。
He is too small to join the Youth League.他的年齡太小，不能加入共青團。
The water is too dirty to drink.水太臟，不能喝。
He was so kind as to be helpful to others.他非常友好，總是幫助別人。
His story is such a sad story as to arouse our sympathy.
他的經歷這么悲慘，引起了我們的同情。
【提示】 “so ...as to do”句式中so接形容詞或副詞；“such ...as to do”句式中such接名詞。
（3）作原因狀語
The children jumped with joy to hear of the arrival of Father Christmas.
孩子們聽說圣誕老人來了就高興得跳了起來。
We were pleased to hear the good news.聽到這個好消息，我們很高興。（4）不定式作插入語
To tell the truth，I have no money with me.坦白地說，我身上沒帶錢。
Strange to say，his hair turned white during the night.
說也奇怪，他的頭發(fā)一夜之間變白了。
