动词加ed和ing规则

动词过去式变化规则与其读音规则规则动词的过去式变化如下：1、一般情况下,动词词尾加 -ed ,如：work -worked play-played wanted-wanted act-acted 2、以不发音的 -e 结尾动词,动词词尾加 -d,如：live-lived move-moved taste-tasted hope-hoped 3、以辅音字母 + y结尾的动词,把-y变为-i 再加-ed,如：study-studied copy-copied cry-cried carry-carried 4、以一个辅音字母结尾的重读闭音节动词,双写词尾辅音字母,再加 -ed,如： stop -stopped 5、不规则动词的过去式变化规律性不强,须多加记忆.go went make made get got buy bought e - came fly-flew 不规则动词的过去式的构成1把动词原形中的i改为a,变成过去式.如：beginbegan,drinkdrank,givegave,ringrang,singsang,sitsat,swimswam 2把重读开音节中的i改为o,变成过去式.如：drivedrove,riderode,writewrote 3改动词原形中的aw ow为ew,变成过去式.如：drawdrew,growgrew,knowknew,throwthrew动词show除外,showshowed4动词原形中的e改为o,变成过去式.如：getgot,forgetforgot 5动词原形中的ee改为e,变成过去式.如：feedfed,meetmet 6动词原形中的eep改为ept,变成过去式.如：keepkept,sleepslept,sweepswept 7动词原形中的eak改为oke,变成过去式.如：breakbroke,speakspoke 8动词原形中的ell改为old,变成过去式.如：sellsold,telltold 9动词原形中的an改为oo,变成过去式.如：standstood,understandunderstood 10以ought和aught结尾,且读音是 :t的过去式.如：bringbrought,buy bought,thinkthought,catchcaught,teachtaught 11以ould结尾且读音为ud的情态动词过去式.如：cancould,shallshould,willwould 12把动词原形中的o改为a,变成过去式.如：ecame,beebecame 13在动词原形后加d或t变成过去式,并且发生音变.如：hearhi heardh :d, sayseisaidsed,meanmi:nmeantment 14动词的过去式与动词原形一样.如：letlet,mustmust,putput,readreadred15不符合上述规律的动词过去式.如：am,iswas,arewere,buildbuilt,dodid,eatate,fallfell,feelfelt,findfound,flyflew,gowent,have has had,holdheld,leaveleft,makemade,maymight,runran,seesaw,taketook 过去式"-ed"的发音规则1动词词尾为"t,d"时,发/ id /音, want wanted 要need needed 需要2动词词尾为清辅音时,发/ t / 音. help helped 帮助laugh laughed 笑look looked 看 kiss kissed 吻wash washed 洗 watch watched 注视3动词词尾为t,d以外之浊辅音或元音时,发/ d /音. call called 叫staystayed 停留crycried 哭过去式是英语语法的一种,表示过去某个时间里发生的动作或状态.一般过去式的动词通常用动词的过去式形式来表示,而动词的过去式是在动词原形的基础上变化的.动词的过去式可分为规则动词和不规则动词.目录过去式,过去时态结构概念：例句：构成用法：1. 22. 1 Be 动词的一般过去时态读法：不规则变化动词表：过去式,过去时态结构概念：例句：构成用法：1. 22. 1 Be 动词的一般过去时态读法：不规则变化动词表：展开过去式,过去时态过去式1、过去发生的而现在已经结束的动作要用一般过去式来表示.2、表示过去某个时间里发生的动作或状态.3、过去习惯性、经常性的动作、行为；过去主语所具备的能力和性格.过去时态表示行为、动作和状态在各种时间条件下的动词形式.过去时态结构指的是过去时态下的动词形式的语法构成.过去式就是动词的变化,表示过去发生的事.一般看到ago,before, in 几几年,就是过去式.work-worked listen-listened 一般的就是直接加ed,特殊的就有一些变化.结构过去时态结构基本形式1、主语+动词过去式+其他；2、否定形式wasn't/weren't 在行为动词前加didn't,同时还原行为动词；一般疑问句Did+主语+do+其他.概念：表示过去的发生动作或过去存在的某种状态例句：A:What did you do last weekend? B:I played football. A:Did you read books? B:Yes,I did. 构成表示一般过去式的动词通常用动词的过去式形式来表示,而动词的过去式是在动词原形的基础上变化的.动词的过去式可分为规则动词和不规则动词.规则动词的过去式变化如下：1一般情况下,动词词尾加 ed ,如：workworked； playplayed；want wanted； actacted 2以不发音的 e 结尾动词,动词词尾加 d,如：livelived； movemoved； decidedecided； declinedeclined； hopehoped；3以辅音字母 + y结尾的动词,把y变为i 再加ed,如：studied tried copied justified cried carried embodied emptied 4以一个辅音字母结尾的重读闭音节动词,双写词尾辅音字母,再加 ed,如：stopped begged fretted dragged dropped planned dotted dripped 5注：不规则动词的过去式变化规律性不强,须多加记忆.go - went,make - made,get - got ,buy - bought ,e - came ,fly-flew ,is/am-was,are-were ,see-saw,bring-brought,do-did,teach-taught, think-thought, say-said,sit-sat. read-read, spend-spent, eat-ate,give-gave,sit-sat,tell-told,write-wrote,feel-felt,find-found,hear-heard,know-knew, put-put,grow-grew,take-took,catch-caught,e-came,bee-became,swim-swam,sweepswept,singsang,drawdrew,以上的1至4条中的发音均有改变,具体分别有/d/ /t/ /id/.而不规则动词的过去式的发音则略有不同,但是有些还是按照一定规律变化的.如以上的：make - made,get - got ,buy - bought ,e - came ,fly-flew ,bring-brought,teach-taught, think-thought, say-said,sit-sat. read-read, spend-spent,give-gave,tell-told,write-wrote,feel-felt,find-found,hear-heard,know-knew,put-put,grow-grew,take-took,catch-caught,e-came,bee-became,swim-swam,sweepswept,singsang,drawdrew.仔细看一看,能发现它们的一些变化规律,也就是说不需要死记硬背这些过去式,知道了原型和变化规律,就可以写出来了.有的变化部分读音也是有规律的.分类记忆是对学习过去式很有帮助的！用法：1表示过去某一时刻或某一段时间内所发生的动作或情况,通常一般过去式带有表示动作时间状语的词,词组或从句,如 yesterday, the day before last, last week, two days ago 等,上下文清楚时可以不带时间状语. I worked in that factory last year. 去年我在那一家工厂工作. I went to the TianLongMountain yesterday. 昨天我们去了天龙山.一般过去时的用法一.概念：一般过去时是表示在过去的时间里发生的动作或状态,通常与表示过去的时间状语连用.二时间状语：yesterday, the day before yesterday, two days ago, long long ago,a minute ago,last year<week, month>, just now, at that time, in those days. 三过去时的用法：1有确定的过去时间状语时要用过去式.例：We had a good time last week. 2表示过去连续发生的动作时,要用过去式.例：The boy closed the door, turned off the window, and then went to bed. 3. 表示过去一段时间内经常或反复的动作,要用过去式.例：She often came to help me at that time. 四.一般过去式的构成形式：Be动词的过去式： <1>肯定句：主语+ be动词的过去式was, were例：He was ill yesterday. She was nine two years ago.They were my students long long ago. <2>否定句：主语+ be动词的过去式was, were+ not 例：He was not ill yesterday.She was not nine two years ago.They were not my students long long ago. <3>一般疑问句：直接把be动词提到句首.例：Was he ill yesterday? 肯定回答：Yes, he was. 否定回答：No, he wasn't.Was she nine two years ago? Yes, she was. / No, she wasn't.Were they your students long long ago? Yes, they were. / No, they weren't. 实意动词的过去式：<1>肯定句：主语+动词的过去式例：He played football last week.She watched TV last night. <2>否定句：主语+ did not +动词原形例：He did not play football last week.She didnt watch TV last night. <3>一般疑问句：Did +主语+动词原形例：Did he play football last week? 回答：Yes, he did./ No, he didn't. Did she watch TV last night? 回答：Yes, she did. / No, she didnt. 五动词变过去式的几种常用规则：1一般动词直接+ ed; 例：look-looked want-wanted listen -listened 2以e结尾的词直接+ d;例：live-lived phone-phoned 3以辅音字母加y结尾, 变y为i加ed;例：try-tried study-studied 4重读闭音节结尾的,词尾只有一个辅音字母,双写词尾辅音字母+ ed;例：stop-stopped plan-planned 5.不规则动词: 动词由原形转变为过去式时不按词尾加"-ed"之变化规则者叫做不规则动词.小学常见的动词不规则过去式如：是be/is/am/are- was, 是are- were, 来e-came, 去go- went, 有have- had, 做/干do- did, 做make- made 读read- read, 放put- put, 切割cut- cut,写write- wrote, 带走take- took, 买buy- bought, 带来bring- brought,想think- thought, 看见see- saw, 说say- said, 说话speak- spoke,打破break- broke, 得到get- got, 跑run- ran, 告诉tell- told,唱sing- sang, 喝drink- drank, 吃eat- ate, 游泳swim- swam,开始begin- began, 偷steal- stole, 遇见meet- met, 卖sell- sold, 坐sit- sat,跑run-ran,读read-read,想要want-want,知道know/known等等表示过去某一时刻或某一段时间内所发生的动作或情况,通常一般过去式带有表示动作时间状语的词,词组或从句,如 yesterday, the day before last, last week, two days ago 等,上下文清楚时可以不带时间状语. I worked in that factory last year. 去年我在那一家工厂工作. I went to the TianLongMountain yesterday. 昨天我们去了天龙山.I stayed at home,yesterday.昨天,我整日呆在家里. 2一般过去时态：表示过去某一时间所发生的动作或存在的状态.谓语动词要用一般过去式.时间标志：yesterday昨天, last weekend上周, last month上个月, last year去年, two months ago两个月前, the day before yesterday前天,in 1990 <在1990年>, in those days 在那些日子里等表示过去的时间状语.如：I was born in 1990. <我出生在1990年>.When did you go to the park? 你是什么时候去的公园.I went to the park last weekend. 我是上周去的公园在上面的句子中第一句属于be动词的一般过去时态；第二句和第三句属于实义动词go的一般过去时态.1 Be 动词的一般过去时态在没有实义动词的句子中使用be动词, am is 的过去式为was; are的过去式为were. 构成：肯定句：主语+was <were> +表语如：I was late yesterday. 昨天我迟到了.否定句：主语+was <were> +not+表语如：We weren't late yesterday. <我们昨天没迟到> 疑问句：Was <Were> +主语+表语如： Do you sick yesterday? 你昨天病了吗？肯定回答： Yes, I was. <是的,我病了.> 否定回答： No, I wasn't. <不,我没病.> 特殊疑问句：特殊疑问词+was <were> +主语+表语如：When were you born? 你是什么时候出生的？读法：规则动词词尾加-ed有三种读音：1. 在清辅音后读作t.如：asked, helped, watched, stopped 2. 在浊辅音和元音后读作d.如：enjoyed, studied, moved, called 3.在t / d后读作id.如：wanted, needed 不规则动词的过去式大体上归纳有以下六条记忆法：1. 以t结尾的词,过去式与原形相同.如：putput, letlet, cutcut, beatbeat 2. 以d结尾的词,把d变成t.如:buildbuilt, lendlent, sendsent, spendspent 3. 以n结尾的词,在词后加t.如：meanmeant, burnburnt, learnlearnt 4.以ow / aw结尾的词,把ow / aw变成ew.如：blowblew, drawdrew, knowknew, growgrew 5.含有双写字母的词,将双写改为单写,在词尾加t.如：keepkept, sleepslept, feelfelt, smellsmelt 6.含有元音字母o / i的词,将o / i变成a.如：singsang, givegave, sitsat, drinkdrank 但也有例外,如get的过去式是got,与第一条不符,仅仅是大多数动词符合.不规则变化动词表：原形过去式过去分词bewas/werebeenbeginbeganbegunbringbroughtbroughtbuyboughtboughtcatchcaughtcaughtecameecutcutcutdodiddonedrawdrewdrawndrinkdrankdrunkdrivedrovedriveneatateeatenfeelfeltfeltfightfoughtfoughtfindfoundfoundflyflewflowngetgotgotgivegavegivengowentgonegrowgrewgrownhavehadhadhearheardheardknowknewknownleaveleftleftloselostlostmakemademademeetmetmetputputputreadreadreadrideroderiddenring rangrungriseroserisenrunranrunsaysaidsaidseesawseensellsoldsoldsendsentsentsetsetsetshutshutshutsingsangsungsitsatsatsleepsleptsleptspeakspokespokenspendspentspentstandstoodstoodswimswamswumsweepsweptswepttaketooktakenteachtaughttaughttelltoldtoldthinkthoughtthoughtthrowthrewthrownunderstandunderstoodunderstoodwearworewornwritewrotewritten现在分词加ing的规则现在分词加ing的规则现在分词是在动词后加上ing 构成.如:starting,working, ing, sitting 等都是现在分词.现在分词的变化规则是固定的,大家用心记一下就可以了.<1>直接在谓语动词后加ing. 例如：going, starting, working. <2>去掉词尾不发音的e,再加ing. 例如 leaving,dining. 注意：如果单词结尾的e发音,则不能去掉,也直接加ing. 例如：see -seeing/agree - agreeing . 另外,有少数动词比较特殊,请用心记住：例如：lie - lying/die - dying/tie - tying/piic - piicking. <3> 对于重读闭音节词,双写末尾字母再加ing. 例如：sitting, beginning. 这一条规律,必须要弄清什么是"重读闭音节".下面再举一些双写的例子：run - running stop - stopping cut - cutting control - controlling回复取消动词不定式、动名词用法要点讲解详细内容不定式作主语动词不定式作主语时,句子的谓语动词常用单数,其位置有以下两种：     <1>把不定式置于句首.如： To get there by bike will take us half an hour.     <2>用it作形式主语,把真正的主语不定式置于句后,常用于下列句式中.如：Itbe名词to do     It's our duty to take good care of the old.     It takes sb+some time+to do     How long did it take you to finish the work?     Itbe形容词for sbto do     It is difficult for us to finish writing the positionin a quarter of an hour.     Itbe形容词of sbto do     It is stupid of you to write down everything the teachersays.     It seems<appears>形容词to do     It seemed impossible to save money.     在句型中,常用表示客观情况的形容词,如：difficult,easy,hard,important,impossible,necessary 等；在句型中,常用careless,clever,good,foolish,honest,kind,lazy,nice,right,silly,stupid,wise等表示赞扬或批评的词.在不定式前的sb,可看作其逻辑主语.这一句式有时相当于Sb is形容词to do句式,如：It'skind of you to help me with my English.=You are kind to helpme with my English.     动名词作主语     Learning without practice is no good.     动名词作主语时,也常用It句式.如：It's +no good<no use,fun,a pleasure,a waste of time>+doing     It's no good reading in dim light.     It's no use sitting here waiting.     It's形容词doing     It's dangerous swimming in the sea in windy days.     这样用的形容词有expensive,nice,tiring等,但important,necessary则不适用于这种结构,应用不定式代替,如：It'simportant for you to keep fit.     There is no+doing     There is no saying what will happen next.     在这一结构中,动名词后常带宾语,相当于"It's impossible to"结构.动词不定式和动名词作主语的区别不定式作主语经常表示具体动作,常与特定的动作执行者联系在一起；而动名词作主语经常表示抽象动作,经常不与特定的动作执行者联系在一起.如：     It's no good eating too much fat.     It's no good for you to eat so much fat.     动名词结构作主语,可以用名词或代词属格形式作逻辑主语.如：     It's no use your pretending that you didn't know the rules.    二、作宾语不定式作宾语以下动词后,只能跟不定式作宾语.如：agree,ask,aim,arrange,choose,decide,demand,expect,fail ,help,hope,lean,long,manage,offer,plan,prepare,pretend,promise,refuse,wish等,这些词大部分可接th at引导的从句.如：     I decided to ask for my money back.     I decided that I would ask for my money back.     When our visit to the farm was over,we expected to startback on foot.     When our visit to the farm was over, we expected that wewould start back on foot.     当复合宾语中的宾语是不定式时,先用形式宾语it代替不定式,把不定式置于补语之后,即：主语动词it补语to do句式.如：     We think it quite important for us to learn a foreignlanguage well.     He feels it his duty to help the poor.     介词but,except,besides+to do<do>     在这种句型中,如介词前有动词do,后面应接不带to的不定式；如无do,则接to不定式,即带do不带to,带to不带do.如：     The enemy soldiers had no choice but to give in.     On Sunday afternoon I had nothing to do but watch TV.    动名词作宾语以下动词后,只能接动名词作宾语,如：admit,appreciate,consider,delay,enjoy,finish,keep,imag ine,mind,miss,practise,resist,risk,save,suggest,don't mind,give up,insist,on, put off等.如：     I suggest spending our summer vacation in a seaside town.     You must give up smoking, for it does too much harm toyour health.     动名词作介词的宾语     I should go to attend the birthday celebration instead of staying at home.     What about inviting Li Jun to make a speech?     动名词前的介词有时可以省略,如：have difficulty<in>doing,have no trouble<in>doing,lose no ti me<in>doing,prevent/stop<from>doing,there is no use<in>doing等.部分动词后面,既可接动词不定式,也可接动名词作宾语,意义不变.如：begin,continue,start,hat e,like,love,need,require,want等.在need,require,want后接-ing形式,表示被动意义,也可接不定式,但要用被动形式,如：Your handwr iting needs improving<tobe improved>. hate,love,like接不定式表示特定的未来事件,接动名词表示目前正在进行的活动或一般的行为.在下列情况下,一般要用不定式：hate,like,love前有would<should>时,如：I'd like to have a cup of coffee.     当谓语动词begin,continue,start等是进行式时,如：Thestudents are starting to work on the di fficult maths problem.     begin,continue,start与know,understand等状态动词连用时,如：I soon began to understand what     was happening.     advise,allow,encourage,forbid,permit等动词后接动名词作宾语,或带不定式作宾语补足语.如：     Our teachers don't permit our swimming in the lake.     Our teachers don't permit us to swim in the lake.     部分动词后接不定式或动名词时,意义差别较大,应根据句子语境选择使用.forget,remember,regret后接不定式,表示现在或未来的动作,接动名词表示动作已经发生.如：     Don't forget fo post the letter for me.     Have you forgotten meeting her in BeijingAirport?     Remember to close the windows before you leave.     I remember writing him a letter a year ago.     We regret to tell you that all of you are not invited toattend the meeting.     They regretted ordering these books from abroad.    mean to do 打算做某事 doing 意味着     I meant to catch up with the early bus.     This means wasting a lot of money.    try to do 设法尽力做某事 doing 试着做某事    You should try to overe your shortings.     Try working out the physics problem in another way.    stop to do 停下一件事去做另一件事不定式作目的状语 doing 停止做某事 On the way to the airport,I stopped to buy a paper.     You'd better stop arguing and do as you are told.     can't help doing 禁不住     to do不能帮助干     They couldn't help jumping up at the news.     Sorry I have lots of work to do.So I can't help to make up the room for you.     go on to do 做不同的事或不同内容的事 doing 继续不停地做某事,指同一动作的继续    He went on to talk about world situation.他接着又谈了世界形势.     We'll go on fighting so long as there is oppression inthe world.     leave off to do 离开某地去干什么目的状语 doing停下某事    It's time to leave off talking and to start acting.     They left off to go fishing.    三、做表语不定式作表语表示具体动作或将来动作；动名词作表语表示抽象的一般行为.To be kind to the enemy is to be cruel to the people.     My chief purpose is to point out the difficulties ofthe matter.    What I would suggest is to put off the meeting. 当主语和表语都是不定式时,其含义一是条件,一是结果例.当主语是aim,duty,hope,idea,mista ke,plan,purpose,suggestion等为中心词的名词词组例时,或以what引导的名词性分句例,不定式说明主语的内容.Our work is serving the people.    What he likes is taking a walk after supper. The story told by Mr.Wang is interesting.     句动名词作表语,与主语部分可以转换,如Serving thepeople is out work,而句中是现在分词作表语,说明主语的性质、状态,现在分词具有形容词的各种特征,另外,动名词作表语还应与进行时态区别开来.四、作定语不定式作定语不定式在句中作定语,置于被修饰的名词或代词之后.如：The next train to arrive is from Washington.    Have you anything to be taken to your sister? Do you have anything to say on the question?     Would you please give me some paper to write on?     My wish to visit France has e true at last.     不定式短语作定语和被修饰词之间表示以下关系：     <1>表示将来的动作例.     <2>与被修饰词之间有动宾关系,如是不与物动词,则需加介词例.     <3>与被修饰词之间有动宾关系,同时与句中其它词之间又有逻辑上的主谓关系时,尽管有被动含义,却仍用主动语态例；如只有动宾关系,而无逻辑上的主谓关系,则需用被动语态例.     <4>不定式作定语时,一般可转换为定语从句,例to arrive=that will arrive.动名词作定语This passage can be used as listening materials. The reading room of our school library can hold 800people.     All moving bodies have energy.     句动名词作定语说明一种性能,即：用来的；第句为现在分词作定语,单个分词作定语常置于被修饰词之前,与被修饰词之间,可构成逻辑上的主谓关系,分词短语作定语常置于被修饰词之后.如：The man standing at the school gate is Professor Hua.    五、不定式作补足语作宾语补足语一些与物动词除要求按宾语外,有时还需要有宾语补足语,说明宾语的行为、状态、特征,这时意思才相对完整.     <1>常要求不定式作宾补的动词有：allow,ask,advise,beg,cause,drive强迫,encourage,expect,fo rbid,force,get,would like<love,hate>,order,permit,persuade,teach,tell,want,warn,wish等.如：Would you like me to give your regards to Mary?     I want you to understand the whole passage clearly.     <2>部分动词后常接to be形容词、名词短语等形式,有时to be可省略,如：believe,consider,discov er,find<=consider>,feel<=think>,imagine,judge,know,prove,think,suppose,see<=understand>,understa nd等.We all believe John<to be>honest.     I consider him<to be>one of the best biology teachers of No. 1 Middle School.     但当不定式是完成式时,to不能省略,如：We consider him tohave been foolish.     <3>感觉动词和使役动词后用作宾补的不定式须省略to.I didn't hear anyone say anything about it.    They make the students do too much homework every day. 这种句式在变为被动语态时,to不能省略,如第句：Thestudents are made to do too much homework     every day.     <4>help,know后面的"to"可有可无.如：     Would you please help me<to> fill in the taxform?     I've never known her<to>be late before.但：He was known to have been to France before.     <5>部分短语动词后,常接不定式作宾补,如：     You may depend on them to be there early.     The Party calls on us to increase production and practise economy.     常这样用的短语动词有：ask for,care for,call on,count on,depend on,wait for,long for渴望, prepare for,wish for等.作主语补足语不定式作主语补足语,和主语构成一种逻辑上的主谓关系.如：He was not allowed to enter the classroom for being late.     The young university student is considered to have great promise.    六、不定式作状语作目的状语     <1> I stayed there to see what would happen.     Henry has decided to go to the hospital to be examinedby the doctor.     <2>有时为了强调,不定式前可加in order或so as.如：     Bob took down my telephone number so as<in order>not toforget it.     有时为强调目的状语可把in order to或不定式置于句首,但so as to不能这样用.在这种句式中不定式部分可转换为so that,in order that,成为目的状语从句,如：     I stayed there so that <in order that>I could see whatwould happen.     <3>在部分表示感情色彩的形容词、过去分词或动词之后可接不定式,如：astonished,glad,happy,laugh ,pleased, sad,smile,sorry,surprised等.We are glad to hear the news.     I was surprised to see that a three-year-old baby could write so well.     在部分形容词后接不定式,用主动形式表示被动意义,这种句型中的主语是不定式的逻辑宾语.如：The question raised by thestudent is difficult to answer.     The room is really fortable to live in.     常这样用的形容词有：fortable,easy,dangerous,difficult,expensive,fit,impossible等.作结果状语     We came home after our holiday to find our garden neat and tidy.     不定式作结果状语还常用在下列句式中.如：soas to;suchas to     I'm not so stupid<a fool> as to put it in writing.我不至于愚蠢到会把它写下来.     I'm not such a stupid fool as to put it in writing.     enoughto     The speed is high enough for us to catch up with thefirst liner.    only to     Jane hurried back only to find her mother dying inthehospital.     tooto     I'm too tired to stay up longer.     但在下列结构中,tooto并非是"太而不能"之意.如：I'm only too glad to have passed the exam.考试与格我太高兴了.too修饰glad to have,相当于veryWe have too much to learn.我们要学的太多了不定式作定语.不定式短语还可作独立成分,用于句首、句中或句末.如：     To tell the truth,the play was a great disappointment tome.     常见的短语有to be exact确切地说,to begin with首先,to do him justice说句对他公道的话,to be sure真的等等.七、动词不定式、动名词的其它用法疑问词不定式结构疑问词who,what,which,when,where,whether,how后可接不定式构成不定式短语,在句中作主语、宾语、表语等.如：When to leave for London has not been decided yet. Mr. Smith didn't know whether to leave or stay there.     I asked Professor Xu how to learn English well.     The question was where to get the medicine needed.     以上例句中疑问词不定式部分,均可转换为相应的从句形式.如：When we shall leavehow I     could learn