不定式的用法

1、不定式的用法 不定式是動詞的一種非謂語形式，它一般由虛詞（或稱不定式符號）to作為標記，如to study, to work等，但在某些情況下也可以不帶to。不定式可以有自己的賓語或狀語。帶有賓語或狀語的不定式叫不定式短語。下面具體談談動詞不定式的用法。    （一）動詞不定式作主語   動詞不定式作主語一定要帶to，謂語動詞用單數。如：   To answer this question is easy.        為了避免句子“頭重腳輕”，英語中往

2、往用it代替不定式，作先行主語（形式主語），將動詞不定式后置。如：   To study foreign languages is very important.        It is very important to study foreign languages.        作形式主語的it只是一個引導詞，沒有具體意義。it 在以下句型中也用作形式主語：   It takes (sb) + 時間詞+不定

3、式+其它，意為“花費（某人）多少時間做某事”。如：   It took her three years to learn Chinese.        It will take me two hours to finish my homework.        How long did it take you to get there?        注意：當動詞

4、不定式作主語時，如果是疑問句，通常用it 作形式主語。如：   Does it cost you a lot of money to collect stamps?        （二）不定式作表語   不定式用于be 動詞后作表語。如：   My wish is to become a scientist.        注意：不定式作表語，to 常省略。如：   All I

5、 did was (to) press the button.        （三）不定式作賓語   不是所有的動詞后面都能用不定式作賓語。在英語中，常用不定式作賓語的動詞有：hope（希望）, wish（希望）, learn（學習）, like（想）, want（想要）, try（試圖、努力）, ask（要求、請求）, plan（打算）, decide（決定）, start（開始）, manage（設法）, agree（同意）, intend（打算、意欲）等。如：   They al

6、l want to watch the football game.        It started to rain when we got home.        He tried to move the table but couldnt.       注意：He used to go to school by bus中的used to go不能理解為“to go”作used的

7、賓語。事實上，usedto+動詞原形（過去經常）是英語中的一種特定結構，用于表示過去經常而現(xiàn)在不再有的習慣。例如：   My father used to smoke a lot, but he doesnt now. 我父親以前經常抽煙，但現(xiàn)在不抽了。   而“be used to +動詞-ing”則表示“習慣于”。例如：   He is used to getting up early.        另外，happen to+動詞原形（碰巧）表示偶然發(fā)生。如：

8、   I happened to see him in the street. 我碰巧在街上看到他。   It happened that I saw him in the street.（注意與上句的句子結構不同）   （四）know 接不定式作賓語需采用“疑問詞+不定式”的結構   英語中，有些動詞后面不能用不定式作賓語，但可以用“疑問詞+不定式”的結構作賓語。如：   He doesnt know what to do.      

9、;  He doesnt know how to do it.      動詞show, tell, teach, wonder可以用“疑問詞+不定式”作直接賓語。   The teacher showed us how to use a computer.      有些動詞既可以用不定式作賓語也可以用“疑問詞+不定式”作賓語。如：   We have decided to hold the English Evening. 

10、0;      We havent decided when to hold the English Evening.        “疑問詞 +不定式”的結構大都可以擴展為從句，如：   I dont know where to find her.        （五）不定式作賓語補足語   不定式用作賓語補足語時，前面一定要有一個賓語，賓語與賓語補足語一起構成復合

11、賓語，它們大都是主謂關系。如：   He asked me to turn down the radio.        me 是賓語，turn down the radio是賓語補足語。   I told them to go by bus.        I wish you to go.        注意：hope, suggest 不能用

12、不定式作賓語。   不定式作賓語補足語常用在下列謂語動詞之后：want（想要）, tell（吩咐）, ask（要、請）, invite（邀請）, order（命令）, allow（允許）, expect（期望）, require（要求）, advise（勸告、建議）, warn（警告）等。   注意：不定式作賓語補足語在下列兩種情況下不能帶to：   1. 謂語動詞是使役動詞make, let, have（當這三個動詞后接不定式作賓語時，都表示“使”、“讓”的意思）時，如：   The sun makes

13、 everything grow. 太陽使萬物生長。    注意：make +反身代詞+過去分詞表示“讓別人怎樣”。如：    She couldnt make herself understood. 她無法讓別人明白她的意思。   He tried to make himself heard. 他設法讓別人聽見他說的話。   2. 謂語動詞是感官動詞see, watch, hear, notice, feel, listen to, look at, observe（觀察）等時，如： 

14、;  I saw the man come out of the office.        注意：謂語動詞是help，作賓語或賓語補足語的不定式可省略 to。如：   Can anyone help me (to) fill in the form?       （六）不定式用作主語補足語都要帶to        They made him leave

15、his own country.（不定式作賓補）   He was made to leave his own country.（不定式作主補）   （七) 不定式作定語   不定式作定語要放在被修飾語之后。如：   Do you have anything to say?        注意：不定式作定語時，如果是不及物動詞，一般應帶有相應的介詞，才能使意思完整。如：   I need a room to work in.&

16、#160;       (八) 不定式作狀語   1. 表示目的，通常放在句末，如要加強語氣，也可放在句首。如：   I got up early to catch the bus.        To catch the bus, I got up early.        注意：不定式表示目的，可以用in order to, so as to，但so

17、as to 不能用于句首。如：   I went there to / in order to / so as to study English.        2. 表示結果，一般用enough to（足夠）, tooto（太而不能）等結構。如：   She was too excited to say a word.        She was so excited that she couldnt say a

18、 word.        He is too young to go to school.        He is not old enough to go to school.        注意：enough 要放在形容詞或副詞的后面。   3. 表示原因，常用“be+形容詞+不定式”結構。如：   Im glad to meet you.

19、        注意：不定式表示原因時一般由人作主語。    (九) 動詞不定式的否定形式   動詞不定式的否定形式為：not+不定式。如：   Our teacher asked us not to be late again.       (十) 不定式的復合結構   英語中，當it 作形式主語時，有for sb to do sth和of sb to do sth兩種情況。

20、試比較：   It is good for you to take exercises every day.        It is good of you to come to see me.        for sb to do sth 表示“做某件事對某人怎么樣”，而“of sb to do sth”則是用形容詞來說明人物性格、特征，表示“某人怎樣”。常用的形容詞有：good, kind, nice, clever, sill

21、y, foolish等。   注意：of sb to do sth句型一般都可以轉換成一個不定式作狀語的句子，而 for sb to do sth 句型則不能。二、考題鏈接與分析1. The doctor thought _would be good for you to have a holiday.(2010 全國II卷) A. this     B. that      C. one    D. it答案為D。從句中的形式主語是it，而for you

22、 to have a holiday 是真正的主語。2.When he _the door, he found his keys were nowhere.   (2009 湖南) A. would open       B. Opened C. had opened       D. was to open 答案為D。系動詞was和to do合在一起構成句子謂語。3. David threatened _ his neighbor to the poli

23、ce if the damages were not paid.   (2009 上海) A. to be reported    B. Reporting C. to report            D. having reported答案為C。threaten后接不定式to do sth作賓語表示“威脅要做某事”。4. Its no use having ideas only. Dont worry. Peter can sho

24、w you _to turn an idea into an act.   (2010 遼寧) A. how    B. who     C. what   D. where答案為A。how表示“怎樣”，強調方式。其他選項不符合題意。5.The fact that she was foreign made _ difficult for her to get a job in that country.  (2010 遼寧) A. so   &#

25、160;   B. much   D. that    D. it 答案為D。句中for her to get a job in that country是動詞不定式的復合結構做made的賓語，difficult是賓語補足語，此處要用it做形式賓語，其他詞沒有這種用法。6. I have a lot of readings _ before the end of this term.   (2010 山東) A. completing     &

26、#160;             B. to complete    C. completed              D. being completed答案為B。由于時間狀語before the end of this term表示未來的時間，所以空格處使用動詞不定式表示將來，充當readings的定語。7. With

27、the world changing fast, we have something new _ with all by ourselves every day.  (2009 重慶) A. deal    B. dealt    C. to deal    D. dealing 答案為C。動詞deal with的邏輯主語是句子主語we。8. With Fathers Day around the corner, I have taken some money out of the b

28、ank _presents for my dad. (2010 全國I卷) A. buy                               B. to buy   C. buying         

29、            D. to have bought答案為B。從銀行取錢的目的是為父親買禮物，故用不定式作目的狀語。9. He hurried to the booking office only _that all the tickets had been sold out. (2006 陜西) A. to tell           B. to be told     C. telling