Grammar 现在完成时.doc

Grammar 现在完成时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.其构成： 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.二、用法：现在完成时既涉及过去,又联系现在.用法一：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.用法二：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：① for＋表示一段时间的词语I have taught English for 19 years.② since＋表示过去时间点的词语He has been at this school since 1986.③ since＋表示过去的时间状语从句I have lived here since I was born.④ since＋一段时间＋ago. I have known him since 20 years ago.三、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?四、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）五、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”,常见的有：come,go,arrive,reach