动词不定式用法解析

 动词不定式是由“to＋动词原形”构成，是非谓语动词的一种，在句中不能单独作谓语。由于不定式具有名词、形容词和副词的特征，因此，在句中可作主语、表语、宾语、定语、状语和补语。　　

一、不定式作主语

【疑难分析】不定式结构作主语，常用it作形式主语，而把真正的主语(不定式)放到句子末尾。for介词短语是不定式的逻辑主语。

【考题链接】The doctor thought 　　　 would be good for you to have a holiday.

(2010 全国II卷)

A. this     B. that      C. one    D. it

【考题分析】答案为D。从句中的形式主语是it，而for you to have a holiday 是真正的主语。

二、不定式作表语　

【疑难分析】不定式往往放在系动词(通常是be)的后面作表语，而become, sound, taste等系动词后面一般不接不定式作表语。

【考题链接】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 

【考题分析】答案为D。系动词was和to do合在一起构成句子谓语。

三、不定式作宾语　

【疑难分析1】不定式常放在agree, attempt, ask, care, choose, decide, desire, determine, expect, fail, hope, intend, manage, offer, prefer, promise, pretend, refuse, want, wish等动词后作宾语。不定式和what, how, whether等特殊疑问词一起，构成动词或介词的宾语。动词不定式可作介词but, except, besides的宾语。如果but前面有实义动词do时，but后面的动词不定式符号to要省略。

【考题链接1】David threatened 　　　 his neighbor to the police if the damages were not paid.                                                            (2009 上海)

A. to be reported    B. reporting

C. to report            D. having reported

【考题分析】答案为C。threaten后接不定式to do sth作宾语表示“威胁要做某事”。

【考题链接2】— It’s no use having ideas only.

— Don’t worry. Peter can show you 　　　
to turn an idea into an act.                                                      (2010 辽宁)

A. how    B. who     C. what   D. where

【考题分析】答案为A。how表示“怎样”，强调方式。其他选项不符合题意。

【温馨提示】不定式与名词构成复合宾语时，通常要用it作形式宾语，而将真正的宾语——不定式放到后面。

【考题链接】The fact that she was foreign made 　　　 difficult for her to get a job in that country.                                                              (2010 辽宁)

A. so       B. much   D. that    D. it 

【考题分析】答案为D。句中for her to get a job in that country是动词不定式的复合结构做made的宾语，difficult是宾语补足语，此处要用it做形式宾语，其他词没有这种用法。

四、不定式作定语

【疑难分析】不定式作定语,被其修饰的名词为不定式所表动作的逻辑主语、逻辑宾语等。不定式的逻辑主语往往是句子的主语，故不定式作定语时往往用主动式；如果不定式的逻辑主语不是句子的主语，该不定式要用被动式。不定式是不及物动词，作定语时，常常须加上合适的介词。

【考题链接1】I have a lot of readings 　　　
before the end of this term.                                            (2010 山东)

A. completing                   B. to complete   

C. completed              D. being completed

【考题分析】答案为B。由于时间状语before the end of this term表示未来的时间，所以空格处使用动词不定式表示将来，充当readings的定语。　

【考题链接2】With the world changing fast, we have something new 　　　 with all by ourselves every day.                    (2009 重庆)

A. deal    B. dealt    C. to deal    D. dealing 

【考题分析】答案为C。动词deal with的逻辑主语是句子主语we。

五、不定式作状语

【疑难分析】不定式作目的状语：不定式的逻辑主语就是句子的主语，因此动词不定式作目的状语时往往用主动式。不定式作结果状语：动词不定式表示一个与主语愿望相反的或出乎主语意料的结果，或用来暗示最初的未能实现的动作。　

【考题链接1】With Father’s Day around the corner, I have taken some money out of the bank 　　　 presents for my dad. (2010 全国I卷)

A. buy                               B. to buy  

C. buying                     D. to have bought

【考题分析】答案为B。从银行取钱的目的是为父亲买礼物，故用不定式作目的状语。

【考题链接2】He hurried to the booking office only 　　　 that all the tickets had been sold out.                                                          (2006 陕西)

A. to tell           B. to be told     C. telling         D. told

【考题分析】答案为B。匆匆赶到订票处，结果被告知票已经卖光。被人告知是出乎
意料的结果且是被动结构，所以用to be told。

六、不定式作补足语　　

【疑难分析】在ask, allow, advise, believe, consider, expect, encourage, find, force, forbid, get, invite, say, suppose, report, think, tell, want, wish, oblige, order, persuade, permit, warn等动词后可以跟不定式作补足语，而且除wish, want, get外，都可以用于被动语态(say只能用于被动语态) 。

【考题链接】In many people’s opinion, that company, though relatively small, is pleasant
.                                                                         (2010 四川)

A. to deal with                 B. dealing with   

C. to be dealt with               D. dealt with

【考题分析】答案为A。“主语+be+形容词+动词不定式”结构中，主语和不定式构成逻辑上的动宾关系，不定式需用及物动词形式。

【温馨提示】在使役动词和感官动词后面作宾语补足语的不定式可省略不定式符号to。

【考题链接】The director had her assistant 　　　 some hot dogs for the meeting.

(2008 全国II卷)

A. picked up                   B. picks up      

C. pick up                     D. picking up

【考题分析】答案为C。have sb. do让某人做某事，用不带to的不定式做宾语补足语。