2014现在完成时详细讲解.doc

现在完成时详细讲解一、 概念：现在完成时表示过去发生或已经完成的动作对现在造成的影响或结果,也可表示过去已经开始,一直延续到现在的动作或状态。 二、 基本结构I have seen that film.He has seen that film.主语+have或has +动词过去分词+其他一般疑问句：Have you seen that film?Yes, I have. No, I havent. Has he seen that film?Yes, he has. No, he hasnt.否定句 ：I havent seen that film.He hasnt seen that film.三、一般过去时和现在完成时对比I taught in this school ten years ago.十年前我在这个学校教书。（现在是否在这个学校教书不知道，只是十年前发生的事情) 叙述了过去某个时间发生了一件事情I have taught in this school since ten years ago.（自从十年前我在这就已经在这个学校教书了，言外之意现在还在这个学校教书，一直延续到现在）叙述了过去发生的事情一直延续到现在。They did their homework an hour ago. (半小时前他们做他们的家庭作业，现在干什么不知道。)They have done their homework since an hour ago.（自从半小时前他们已经做他们的家庭作业，言外之意现在还在做家庭作业，一直延续到现在。）四、练习1. She has eaten a banana already._(一般疑问句，并作否定回答)_（否定句）2. They have come back from America already. 3. I have studied English for six years. 4. Lucy and Lily have stayed here since two hours ago. 5. Lucy has stayed at school for two weeks. 6. I have worked here for two weeks. 7. Nick has been a teacher for five years. 8. Lily has had breakfast. A. 用 already或 yet1) Have they taken down the old pictures _? No, not _.2) Most of us have finished our compositions _3) He said he hadnt visited the exhibition _.B.用 since或 for1) We have learned five lessons _ the beginning of this term.2) Mrs Liao has been in hospital _last week. 3)She has been here last Wednesday 4)We have studied English two years 5)He has lived here he left Shanghai 6)They have known each other about five months 7) Miss Zhao has worked in the factory ten years ago.8) I have stayed at my aunts _two weeks.I.用所给动词的适当形式填空。I_ already _ (see) the film. I _ (see) it last week._ he _(finish) his work today ? Not yet._ you _(be) to Hong Kong ? Yes, I _ (be) there twice._ you ever _(eat ) chocolate sundaes ? No, never.My father _ just _ (come) back from work. He is tired now.Wheres Li Ming ? He _ (go) to the teachers office.Shanghai _ (be) a small town hundreds of years ago. Now it _ (become) a large city.I _ (work) here since I _ (move) here in 1999.So far I _(make) quite a few friends here.How long _ the Wangs _(stay) here ? For two weeks.II.句型转换(每空一词)。1. I have been to Macau before. (改为否定句)I _ _ been to Macau before.2.He hasnt come to school because hes ill (就划线部分提问)_ _ he come to school?3. He has learned English for 5 years. (就划线部分提问)_ _ _ _ learned English ?4. I bought a new bike just now. (用just改写)I _ just _ a new bike.5. We began to learn English three years ago. (改为同义句)We _ _English _three years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+ ./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：Arrive be here begin (start)be ondie be dead come back be backleave be away (from) fall ill(sick, asleep)be ill(sick, asleep)get up be up go out be outfinish be over put on wear 或be onopen be open join be in或 be a member ofclose be closed go to school be a studentborrow keep buy/get havecatch (a cold) have(a cold) get to know knowbegin to study study come to work workmove 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 America.（他到美国去了。他不在这里）He has been to America.（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）（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 uncle bought the new car two months ago.My uncle has_ the new car _two months ago.II. 用have been和have gone填空。1. Mother isnt here. She _ to the barbers.2. _ you ever _ abroad before?3. There you are at last! Where _ you _?4. Tom and Mary have just come in. They _ to a party.5. Tom and Mary arent here. They _ to a Party.6. My father _ to New York. He left this morning.7. My mother _ to the supermarket and she has taken my bag with her.8