现在完成时1.构成现在完成时是由助动词 have(has)+动词的过去分词构成。助动词have(has)表明事情发生于现在。它和主语的人称、数要保持一致。过去分词在句子中做谓语，说明句子的含义。2.用法（1）动作发生在过去某个不确定的时间，但对现在有某种影响和结果。常被 just、already、yet 等副词修饰。如：-Have you had lunch yet? -Yes,I have. Ive just had it.你（已经）吃午饭了吗？ 我刚刚吃过。（现在我不饿了）（2）表示从过去某一时刻开始一直持续到现在的动作或状态。这个动作可能刚停止，可能仍然在进行。常带有 for 和 since 等表示一段时间的状语。如：He has taught here since 1981他自 1981 年就在这儿教书。（可能还要继续教）I havet seen her for four years.我有四年没见到她了。（3）表示说话前发生过一次或多次的动作，现在成为一种经验，一般译为汉语“过”，常带有 twice,ever,never,three times 等时间状语。如： I have been to Beijing twice.我去过北京二次。3.现在完成时的时间状语（1）现在完成时属于现在时范围，故不能和过去的时间状语连用。如：yesterday,last Sunday,in1990,three years ago 等。但是，在强调动作产生的后果和影响时，可以和一些表示不确定的时间状语连用。a. 用副词 already 和 yet。already 一般用于肯定句中，yet 一般用于否定句和 疑问句中。如：We have already finished our homework.我们已完成作业了。They havent finished their homework yet.他们还没有完成作业。b.用 ever 和 never。多用于否定或疑问句中，表示“曾经”或“从未“等。 如：-Have you ever been to the Great Wall?你曾经去过长城吗？-I have never been to the Great Wall.我从未去过长城。c.用表示到说话为止的过去时间状语，如 just,before,up to now,the past few years 等。例如：I have seen her before,but I can not remember where. 我以前见过她，但记不起在哪里见过。He has been there three times the last few days. 近几年他去过那里三次了。d.用包括“现在”在内的时间状语，如：now,today,this morning(month,year,term)等。例如：-Have you met him today?-No,I havent. 今天你见过他吗？我 没有。 How many times have you been there this year? 今年你去过那里多少次？（2）现在完成时可以和带有 since 或 for 等表示“一段时间”的状语 连用,表示动作或状态从某一时刻开始，一直持续到现在。如：I havent seen him for two years. 但是，像 come,arrive,buy 等终止性动词不能与表示“一段时间”的状语连用。要用，必须改为“be（在）”等延续性动词来表述。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 backleave be away fall ill(sick,asleep)be ill(sick,asleep)get upbe 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 schoolbe a studentborrow keep buy have catch(a cold) have(a cold) get to know knowbegin to studystudy come to workwork 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。4.现在完成时和一般过去时的区别现在完成时和一般过去时都表示在过去完成的动作。但现在完成时强调的是这一动作与现在的关系。如对现在产生的结果或影响等，而一般过去时只表示动作在过去某一时刻发生，不表示和现在的关系。试比较：I have lost my new book. 我把新书丢了。（现在还未找到）I lost my new book yesterday. 我昨天把新书丢了。（昨天丢的，现在找到与否没说明）5.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）”，常用于第三人称，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。（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。一、 单项选择 1. Li Hong has _ the army for 2 years. A. joined B. be in C. been in D. joined in 2. We have been friends since _. A. children B. five years C. five years ago D. five years before 3. Mike _ the story for a month. A. has bought B. has had C. had had D. has borrowed 4. You _ that question three times. A. already asked B. have already asked C. already have asked D. asked already 5. Those foreign friends left Guangzhou _. A. since last week B. a week ago C. for a week D. since a week ago 6. I _ at this school for two years. A. am studying B. study C. studied D. have studied 7. They _ in the city since last summer. A. live B. didnt live C. have lived D. live 8. Mrs. Wang has lived in Haikou _ 1992. A. since B. from C. after D. in 9. Mr. Black _ China since the summer of 1998. A. has been to B. has been in C. has come to D. came to 10. His father _ for years. A. has died B. has been dead C. died D. dies 11. Mary _ to see the films because she _ it twice. A. wont go, saw B. wont go, will see C. wont go, has seen D. didnt go, sees 12.- Would you like some more food? -Thank you. I _ enough. A. will have B. have had C. have D. had 13. _ you _ England? Yes, it _ a beautiful country. A. Will, gone to, was B.Have, been to, is C. Had, been to, is D.Have, gone to, is 14. -_ you _ to Beijing? -No, I _.I _ there early next month. A. Have, been, havent, am going B. Had, been, hadnt, am going C. Have, gone, havent, was going D. Did,go, didnt, was going 15. -You sister _ to London to study English. Is that true? -Yes , she _ there for two months. A. has been, has been B. will go, has gone C. gone, will be D. has gone, has been 16. He has a computer of his own. He _ it two days ago A. bought B. bought C. bought D. has bought 17. Where is Li Lei? He _ Shanghai.