现在完成时一、知识梳理要点一：现在完成时用来表示之前已发生或完成的动作或状态，但它的影响现在还存在；也可表示持续到现在的动作或状态。

要点二：1、构成：have (has) +过去分词。

规则变化的过去分词与过去式的变化一样，在动词词尾加ed; 不规则变化的过去分词见不规则动词表，需要同学记忆。

现以see the film为例将现在完成时的肯定句，否定句和疑问句列表如下：肯定句：I/You/We/They have seen the film. He/She /It has seen the film.否定句：I/You/We/They have not/ haven’t seen the film.He/ She/It has not/hasn’t seen the film.疑问句：Have I/you/they seen the film? Yes, you/ we/I/they have. No, you/ we/I/they haven’t.Has he/she/it seen the film? Yes, he/ she/ it has. No, he/ she/ it hasn’t.2、变化规则：与动词过去式规则相同。

①一般直接在词尾加上ed。

look —looked②以e结尾的动词，直接加d。

move —moved③以y结尾，y前面是辅音字母的动词，变y 为i，再加ed。

carry —carried④部分动词需双写尾字母，加ed。

stop —stopped⑤不规则变化AAB型ABB型用法：现在完成时既涉及过去，又联系现在。

用法1：表示过去发生或已经完成的某一动作对现在造成的影响或结果。

常与just（刚刚），already（已经），never（从来没有），ever（曾经），before（以前），yet（仍然），once（一次），twice（两次），many times（很多次），how many times（多少次），so far（迄今为止），during the past（last）three years（最近三年来）等连用。

※副词的位置：①just常用于肯定句中，放在have / has后，He has just come .②never表示否定, 放在have / has后, He has never visited the Great Wall.③ever用于疑问句中,句型为: Have / Has＋主语＋ever＋过去分词？“…曾经……过吗？”用于询问某人过去的经历。

Have you ever been to the farm？④before用于句末，The woman has never heard of that before.⑤yet 用于句末或not 之后. Has the train arrived yet? No, not yet.⑥already用于肯定句, have / has 之后或句末.We have already finished it.⑦so far用于句首或句末. So far, we have visited the moon.用法2：表示过去已经开始，一直延续到现在的动作或状态。

时间状语有：①for＋表示一段时间的词语I have taught English for 19 years。

②since＋表示过去时间点的词语He has been at this school since 1986.③since＋表示过去的时间状语从句I have lived here since I was born.④since＋一段时间＋ago. I have known him since 20 years ago.用法3：表示到现在为止多次发生的动作，常带有twice, ever, never, three times等时间状语。

I have been to Beijing twice. 我去过北京两次。

He has watched the film twice. 这部电影他已经看过两遍了。

要点四：现在完成时态中，可以和表示一段时间状语（for，since，how long, all one’s life）连用的动词必须是表示延续的情况或动作的动词，即延续性动词。

如：be，have，know，live，work，study，learn，teach，keep，speak，talk，draw，wait，wear，walk，sleep，drive，write，do，clean等。

I have been a teacher for nearly 20 years. How long has he lived here?要点五：延续性动词的现在完成时可和包括“现在”在内的（到说话时仍未结束）表示一段时间的状语连用。

如this morning，today，this week，these daysHe has been to Beijing three times this year.He has written two letters this morning.（说话时间在上午）He wrote two letters this morning.（说话时间在下午或晚上）要点六：英语中还有一些动词的意义决定它们所表示的动作不能延续,只是一瞬间就结束的动作,这类动词叫做“非延续性动词”（短暂性动词/瞬间动词），常见的有：come，go，arrive，reach，see，hear，close，open，leave，begin，start，lose，buy，fall，join，die，get up，become，borrow，lend，find，finish，receive等。

这些动词可用于现在完成时，说明某个动作的结果还存在，但不能和表示一段时间的状语（how long，for，since）连用。

He has come back.（√）He has come back for two hours.（×）※但在否定句中，非延续性动词也可用表示一段时间的状语来修饰（因为非持续性动词的这种否定形式构成一种状态，而这一状态是可以持续的），如I haven’t heard from my father for a long time.We haven’t seen him since 1999.【注意】：当终止性动词（非延续性动词）与表示一段时间的状语（how long，since，for，all one’s life）相矛盾时,改正错句的方法有如下几种:（1）用副词ago把现在完成时的句子改为一般过去时.He has come back for two weeks.（错）改为:He came back two weeks ago.（正）I have lost my bike for ten days. （错）改为:I lost my bike ten days ago. （正）（2）用“It is / has been＋时间＋since＋一般过去时态”句型来改写。

He has joined the League（社团）for 3 years. （错）It is 3 years since he joined the League.I have bought the book for 5 days. （错）It is 5 days since I bought the book. （正）He has died for 20 years. （错）It is 20 years since he died. （正）（3）用“时间＋has passed＋since＋一般过去时态”句型来改写。

He has left home for 20 years. 改为:Twenty years has passed since he left home.He has lost his pen for 2 days. 改为:Two days has passed since he lost his pen. （4）用系表结构来改写.He has died for 20 years. 改为: He has been dead for 20 years.The factory has opened since 1999. 改为:The factory has been open since 1999.How long has he left? 改为:How long has he been away?（5）用相应的延续性动词替代非延续性动词。

He has bought the book for two weeks. 改为:He has had the book for two weeks. 常见的相应转换形式如下:borrow / lend→keep,buy/catch→have,finish / stop/end→be over, begin / start→be on , open→be open ,close→be closed,die→be dead ,leave→be away（from）, get up→be up,fall asleep→be asleep , fall ill→be ill,Married→be married get to know→know,lose→be lost,become→be,begin to study→study,join→be in / be a member of,receive / get a letter→have a letter ,catch / get a cold→have a cold,join the army→be in the army /be a soldier, return / come back / get back→be back,go to school→be in school / be a student, arrive /come / go / move / reach /get to→be in /at / be here /be there,他参军已有三年.He has joined the army for three years.（错）改为:He has been in the army for three years / since three years ago.He has been a soldier for three years / since three years ago.He joined the army three years ago.It is three years since he joined the army.Three years has passed since he joined the army.要点七：现在完成时中应注意的几个问题have/has gone to；have/has been to；have/has been in的区别have/has gone to：已经去了，还没有返回；强调“去了”，现在人不在说话的现场have/has been to：曾经去过某地，现在已经回来了，后面可接表示“次数”的状语；have/has been in：表示某人“已在某地停留一段时间，现仍在那里”，其后常带表示一段时间的状语。