一般完成时讲解.doc

一、现在完成时的“完成用法”和“未完成用法”1.现在完成时的完成用法 现在完成时的完成用法指的是动作发生在过去某一时刻并已结束，但该动作对现在产生了影响，与现在情况具有因果关系。例如：He has turned off the light.他已把灯关了。(动作结束于过去，但说明的是现在的情况-灯现在不亮了。)现在完成时完成用法的特点是动作不延续，因此，该时态只能与表示不定的过去时间状语(如：already，yet，before，recently等)、频度时间状语(如：never，ever，once等)、包括现在时刻在内的时间状语(如：this morning month year.，today等)连用。例如： Have you found your pen yet？你已找到你的钢笔了吗？2.现在完成时的未完成用法 现在完成时的未完成用法指的是动作开始于过去某一时刻，一直延续到现在，或可能还要继续下去。例如：He has lived here since 1978.自从1978年以来，他一直住在这儿。(动作起始于1978年，一直住到现在，可能还要继续住下去。) I have been in the army for more than 5 years.我在部队已经呆了五年多了。(动作开始于5年前，一直延续至今，有可能还要继续下去。) 此种用法的句中常需一个表示一段时间的状语(由since或for引导)，或表示与现在时刻相连的时间状语(如：up to now，so far到目前为止)等。例如：I have heard nothing from him up to now.到目前为止我没有他的任何消息。 注意：(1)现在完成时的未完成用法只适用于延续性动词，不可用于终止性动词，即瞬间完成或延续时间很短的动词。如：come，go，arrive，leave，join，become，die等。(2)现在完成时常见两种句型：主语have / has beenfor短语 It is一段时间 since从句 例如：He has been in the League for three years.或It is three years since he joined the League. 他入团已三年了。3、延续性动词和终止性动词的概念英语中，动词按其动作发生的方式、动作发生过程的长短，可分为延续性动词和终止性动词。延续性动词表示能够延续的动作，这种动作可以延续下去或产生持久影响。如：learn, work, stand, lie, know, walk, keep, have, wait, watch, sing, read, sleep, live, stay等。终止性动词也称非延续性动词、瞬间动词或短暂性动词，表示不能延续的动作，这种动作发生后立即结束。如open, close, finish, begin, come, go, arrive, reach, get to, leave, move, borrow,buy等。4、延续性动词的用法特征1.延续性动词可以用于现在完成时，其完成时态可与表示段时间的状语连用。表示段时间的短语有：for two years, during the past three years, since last year, how long等。如：I have learned English since I came here.自从我来到这儿就学英语了。2.延续性动词不能与表示短暂时间的点时间状语连用。如：It raind at eight yesterday morning.(误) rain为延续性动词，而at eight表示点时间，前后显然矛盾。如果用延续性动词表示一瞬间的动作，可以借助come, begin, get等终止性动词来表示。上句可改为：It began to rain at eight yesterday morning.(正)又如：-When did you get to know Jack?-Two years ago.-Then youve known each other for more than two years.-Thats right.5、终止性动词的用法特征1.终止性动词可用来表示某一动作完成，因此可用于现在完成时。如：The train has arrived.火车到了。Have you joined the computer group? 你加入电脑小组了吗？2.终止性动词表示的动作极其短暂，不能持续。因此，不可与表示一段时间的状语连用(只限肯定式)。如：(1)他死了三年了。 误：He has died for three years.正：He has been dead for three years. 正：He died three years ago.正：It is three years since he died. 正：Three years has passed since he died.(2)他来这儿五天了。 误：He has come here for five days.正：He has been here for five days. 正：He came here five days ago.正：It is five days since he came here. 正：Five days has passed since he came here.(1)、(2)句中的die、come为终止性动词，不能与表示段时间的状语连用。那么，应如何正确表达呢？可以采用下面的四种方法：(1)将句中终止性动词转换为相应的延续性动词，如上面两例中的第一种正确表达方式。下面列举几例：leavebe away, borrowkeep, buyhave, begin/startbe on, diebe dead, move tolive in, finishbe over, joinbe in/be a member of, open sth.keep sth. open, fall illbe ill, get upbe up, catch a coldhave a cold。(2)将句中表示段时间的状语改为表示过去确定时间的状语，如下面两例中的第二种正确表达方式。(3)用句型It is+段时间+since.表达原意，如上面两例中的第三种正确表达方式。(4)用句型时间+has passed+since.表达原意，如上面两例中的第四种正确表达方式。3.终止性动词可用于现在完成时否定式中，成为可以延续的状态，因而可与表示一段时间的状语连用。如：He hasnt left here since 1986.I havent heard from my father for two weeks.4.终止性动词的否定式与until/till连用，构成not+终止性动词+until/till .的句型，意为直到才。如：You cant leave here until I arrive.直到我到了，你才能离开这里。I will not go to bed until I finish drawing the picture tonight.今天晚上直到我画完画，我才上床睡觉。5.终止性动词可以用于when引导的时间状语从句中，但不可以用于while引导的时间状语从句中。when表示的时间是点时间(从句谓语动词用终止性动词)，也可以是段时间(从句谓语动词用延续性动词)。而while表示的是一个较长的时间或过程，从句谓语动词用延续性动词。如：When we reached London, it was twelve oclock. (reach为终止性动词)Please look after my daughter while/when we are away. (be away为延续性动词短语)6.终止性动词完成时不可与how long连用(只限于肯定式)。如：误：How long have you come here? 正：How long have you been here?正：When did you come here?二、现在完成时与一般过去时的区别1. 一般过去时表示过去某个时间发生的事、存在的状态或经常发生的动作。说话的侧重点只在于陈述一件过去的事情，不强调对现在产生的影响。如：He visited Guilin in 1998.他1998年参观过桂林。(只说明去桂林的时间)2. 现在完成时表示动作发生在过去，对现在造成了影响或产生了结果。不与确定的过去时间状语连用。如：Jill has bought a new computer.吉尔买了一台新电脑。(着重点是现在有了一台新电脑)3. 两种时态的区分(1)一般过去时的谓语动词用过去式，而现在完成时的谓语基本构成是助动词have /has +过去分词。如：The film started at 7 oclock. He has been a teacher for many years.(2)一般过去时通常与表示过去的时间状语连用。如：yesterday, last week, two years ago, just now, in 2002等；而现在完成时则常与just, already, ever, never等副词和these days, this week, since., for.等表示一段时间的状语连用。看看以下的几组句子，有什么区别？ Have you seen the film?(A) Did you see the film?(B)说明 你看过这部电影吗？(A)句强调的是被问者对剧情是否了解；(B)句强调的是看这部电影的动作是否发生过，并不强调是否知道其内容。 How has he done it?(A) How did he do it?(B)说明他是怎么做的这件事？(A)句强调的是他做这件事的方式对现在产生了某种影响；(B)句单纯的询问做这件事的方式。 He has lived in Beijing for 8 years.(A) He lived in Beijing for 8 years.(B)说明他在北京住了8年。(A)句讲的是到目前为止他在北京住了8年，可能还会继续在北京住下去。(B)句讲的是他在北京住过8年，现在不在北京了。三、现在完成时考点例析现在完成时是较难掌握、中考考查较多的时态。涉及的考点有：一、考查其构成助动词have (has) +动词过去分词构成现在完成时。如：1. Kates never seen Chinese films，_ ? A. hasnt she B. has she C. isnt she D. is she析：陈述句部分含否定词never,简略问句部分要用肯定式，又因Kates是Kate has的缩写，故选B。2. His uncle has already posted the photos to him. (改为否定句)His uncle _ posted the photos to him _. 析：already常用在肯定句中，yet常用在否定句、疑问句中，故填hasnt, yet。3. -Ann has gone to Shanghai. -So _her parents. A. has B. had C. did D. have析：so+助/系/情态动词+主语结构中的动词形式应与前句结构中动词形式保持一致，又后句的主语为her parents是复数,故选D。二、考查其用法与标志词(一)当句中有never, ever, just, already, yet, before等时，常用现在完成时。如：1. -Mum, may I go out and play basketball? -_you_ your homework yet? A. Do; finish B. Are; finishing C. Did; finish D. Have; finished2. -_ you _anywhere before? -Yes, but I cant remember where I_A. Did; surf; surfed B. Have; surfed; surfed C. Did; surf; have surfed D. Have; surfed; have surfed析：据yet和before可知,应用现在完成时，故1题选D，2题选D。(二)当句中有for +段时间或since +点时间等时，主句常用现在完成时，谓语动词必须是延续性动词，若是非延续性动词，要改为延续性动词或表状态的词(短语)。如：1. His brother has been to Stone Forest twice_he came to Yunnan. A. after B. before C. since D. for析：主句用的是现在完成时，而从句用的是一般过去时，故选C。2. Tom_the CD player for two weeks.A. has lent B. has borrowed C. has bought D. has had析：A、B、C均为非延续性动词，在肯定句中不与表段时间的短语连用，故选D。3. I_a letter from him since he left. A. didnt receive B. havent got C. didnt have D. havent heard析：据since可知，应排除A、C，hear from sb.=receive/get/have a letter from sb.意为收到某人的来信，故选B。三、考查have/has been (to, in)/have/has gone (to)的区别。如：1. -Have you ever_Lintong to see the Terra Cotta Warriors?-Yes, I have. A. went to B. gone to C. been in D. been to析：据句中的have，排除A，B项意为去某地了，C项意为一直呆在某地，D项意为去过某地，符合题意，故选D。2. My parents _ Shangdong for ten years. A. have been in B. have been to C. have gone to D. have been析：本题句中有for+段时间结构，据此可排除C，B项意为去过某地，不合题意，D项缺介词，故选A。四、考查现在完成时与其他时态的联系和区别。如：1. Suns aunt has gone there for ten years.(改成正确的句子)析：非延续性动词与段时间连用时，除了把非延续性动词改成延续性动词外，还可把动词改为一般过去时或借助句型Its +段时间+since+从句进行句子转换。故答案为：Suns aunt has been there for ten years. /Suns aunt went there ten years ago. /Its ten years since Suns aunt went there. 2. Susan has been in this city for more than ten years.(改为同义句)_more than ten years _Susan _to this city. 析：据上题分析，且since引导的从句要用一般过去时，故填It is, since, came。3. I wont go to the concert because I _my ticket. A. lost B. dont lose C. have lost D. is coming析：因我丢了票的动作发生在过去，而且对现在造成了我不能参加音乐会的结果，符合现在完成时所表示的含意，故选C。短暂性动词，延续性动词和现在完成时短暂性动词是指动作一旦发生就立即结束。它不能和一段时间连用。这类动词有：go, come, arrive, leave, begin, start, join, marry 等；短暂性动词的肯定式不能与表示一段时间的for或since或how long等状语连用。例如：His father got ill. I have received his letter.但是，不可以说：His father got ill for a week.I have received his letter for three days.在否定句中，短暂性动词可以和表示一段时间的状语连用。例如：We havent heard from Jane for a long time.I suppose something must have happened to her.延续性动词是指动作发生后还可以延续一段时间或者相当长的一段时间。如：live, work, study, learn, sleep等，延续性动词可以和表示一段的时间状语连用。值得注意的是，表示一段时间的状语除了“for+一段时间”外，还有since+n./从句（时间点），since+时间段+ago，疑问词how long，in the past+时间段，all these+时间段，fromto（时间点）以及till/until+n./句子等等。例如：How long _ your brother joined the army?A. has B. had C. is it since D. was there that通过审题，答案B和D很容易被排除，但是稍不注意便会选中答案A；殊不知how long为一段时间的状语，不能与非延续性动词短语has joined连用，所以这题的正确答案是C。另外，动词的延续性与非延续性还体现在这两种句型中：延续性动词的肯定式+till/ until 短暂性动词的否定式+till/ until请看例句：We waited until he came.I didnt go to bed until my father came back home last night.如果短暂性动词与表示一段时间的时间状语连用，必须将短暂性动词改为延续性动词。现归纳总结一下由非延续性动词到延续性动词的转换： arrivebe here begin(start)be on die be dead come backbe back leave be away (from) fall ill(sick, asleep)be ill(sick, asleep) get upbe up go out be out finish be over put on wear 或be on open be open join be in或 be a member of close be closed go to schoolbe a student borrow keep buy/get have catch(a cold) have(a cold) get to know know begin to studystudy come to workworkmove to live in finish/end be overcome to be in sit down be seatedmarry be married dress be dressed等如：He has been a soldier for three years. 他参军三年了。 His father has been dead for two years. 他父亲去世二年了。 The film has been on for ten minutes. 电影已开始十分钟了。We have studied English for three years. 我们（开始）学英语已三年了。How long can I keep this book? 这本书我可以借多长时间？除了用上面的转化形式之外，还可以用其他的表达形式：A. It is/ has been+时间+since（动词用过去式），B. 主语+谓语（过去时）+时间+ago。例如：Its five days since I received his letter.His father died three years ago.看一个句子可以用以下几种说法：他离开上海已经3天了。He left Shanghai three days ago.He has been away from Shanghai for three days.He has been away from Shanghai since three days ago.It is/ has been three days since he left Shanghai.Three days has passed since he left Shanghai.几点注意事项:（1）have been(to)与have gone( to)的区别：have been(to)表示“去过某地（现在已经回来了）”，可用于各人称；have gone(to)表示“去某地了（说话时某人不在当地）”，可能在去的路上，可能已在某地，也可能在回来的路上，总之，人不在这里。常用第三人称作主语。，前者可与once ,never, several times等连用，后者则不能。如：They have been to Beijing twice. 他们去过北京两次。 He has gone to Beijing . 他去北京了。注意比较下面几组句子的意义：He has gone to Amercia.（他到美国去了。他不在这里）He has been to Amercia.（他去过美国。现已回来）He has been in Shanghai.（他在上海呆过。现在不在上海）He has been in shanghai for years.（他在上海多年。现在还在上海）He has taught English.（他教过英语现在不教了）He has taught English for years.（他教英语多年了。现在还在教）（2）如单纯表示一段时间，或强调一段时间，虽有since一词，也不必用完成时。如：It is two years since his father died.=His father has been dead for two years. 他父亲去世已有三年了。（3）终止性动词现在完成时的否定式，已变成一种可以延续的状态，因此可以和表示一段时间的状语连用。 如：I havent left here since 1997. 自从1997年以来，我一直没有离开过这儿。Exercises:I. 句型转换：1. Mr. Li began to teach English in this school in 1999.（同义句） Mr. Li _ _ English in this school since 1999.2. The factory opened ten years ago.（同义句 The factory _ _ _ for ten years.3. John left Beijing three years ago. （同义句）Three years _ _ _ John _ Beijing.John_ _ _ _ Beijing _ three years.4. His company opened in 2003. （同义句His company _ _ _ since 2003.5. My father bought the car half a year ago. （同义句My father _ _ the car _ half a year.6. We got to know each other for about 15 years. （同义句We _ _ each other _ about 15 years.7. The film began ten minutes ago. （同义句The film _ _ _ for ten minutes.8. I borrowed this book two weeks ago. （同义句I _ _ this book for two weeks.9. My father came back the day before yesterday.My father has _ _ for two days.10.My uncl