现在完成时的句子（英语语法专练—现在完成时）
一、结构
1.主语+have/has+动词的过去分词......
动词的过去分词分为规则变化和不规则变化。规则变化如下：①一般情况下在动词后加ed。
②以e结尾的动词，在后面直接加d。
③以辅音字母+y结尾的动词，把y变为i再加ed。
④以重读闭音节结尾的动词，单词末尾只有一个辅音字母，该重读音节上只有一个元音音素，这个元音音素是一个元音字母发出来的，那么就需要双写单词末尾的辅音字母，再加ed。
* 动词的过去分词不规则变化见八（下）、九年级教材后附表，需特殊记忆。
2.陈述句肯定式（肯定句）：主语+have/has+动词的过去分词......
3.陈述句否定式（否定句）：主语+haven't/hasn't+动词的过去分词......
4.一般疑问句：Have/Has+主语+动词的过去分词......？Yes，主语+have/has.（肯定回答） No,主语+haven't/hasn't.（否定回答）
二、用法
1.表示动作发生在过去某个不确定的时间，但对现在造成了某种影响。常just, already, yet等副词修饰。如：She hasn't finished her homework yet.
2.表示行为或状态从过去一直持续到现在，并可能继续持续下去，常与for短语，since引导的时间状语等连用，或用于How long...的句型中，表示持续的时间。如：How long have you been like this?/She has taught English for five years.
注意：for后接一段时间，而since后多接时间点。
3.表示说话前发生过一次或多次的动作，或已有过的一次经历，现在成为一种经验。常与twice，ever, never, three times等连用。如：I have seen this film twice.
三、时态标志
1.现在完成时态属于现在时的范畴，故不能与过去时间状语连用。但在强调动作产生的后果和影响时，可以和一些表示过去的、不确定的时间状语连用。
（1）already用于现在完成时态肯定句中，偶尔用于一般疑问句末尾，表示惊讶的语气；yet一般用于否定句和疑问句中。如：Have you finished your homework already?/We have already finished our homework.
（2）ever和never多用于否定句或疑问句中，表示"曾经"或"从未"。如：I have never been to the Great Wall.
（3）just，before,in the past few years等，表示到说话为止发生的动作。如：She has been there twice in the past few years.
（4）now, today, this morning,these days等，表示包含"现在"在内。如：How many times have you been there this year?
2.表示过去某一时间发生的动作或状态一直持续到现在，应用延续性动词或表示状态的动词。短暂性动词不能与for表示一段时间的状语连用，也不能用于how long...句型中。如需连用，应将某些短暂性动词转换为相应的延续性动词。常用的短暂性动词及对应的延续性动词如下：arrive（be here),begin/start(be on),die(be dead),come back(be back), leave(be away), fall ill/sick/asleep(be ill/sick/asleep),finish(be over),put on(wear/be on),open(be open), join(be in/be a member of...),close(be closed),borrow(keep), buy(have), catch a cold(have a cold), get to know(know), begin to study(study),come to work(work),go out(be out)
如：How long have you keep this book?/She has had the watch for three days.
四、几点注意事项
1.现在完成时态与一般过去时态的区别：现在完成时态强调动作与现在的关系，如对现在产生的结果或影响等。一般过去时态表示在过去某一时刻发生，不表示和现在的关系。如：I seen this film./I saw this film yesterday.
2.have/has been to表示去过某地（现在已经回来了），可用于各人称；have/has gone to表示去某地了（说话时某人不在现场）。常用于第三人称。have/has been in表示待在某地，一直在某地。如：They have been to Shanghai three times./They have gone to Shanghai./They have been in Shanghai for three years.
3.关于since 的几个句型：
（1）主语+have/has+动词的过去分词+since+一般过去时态的句子。如：She has been away from Shanghai since she went to college.
（2）主语+have/has+动词的过去分词+since+时间点。=It is/has been+时间+since+一般过去时态的句子。=时间has passed+since+一般过去时态的句子。如：She has worked in this hospital since ten years ago.=It is/has been ten years since she worked in this hospital.=Ten years has passed since she worked in this hospital.
4.个别短暂性动词的否定形式可以表示状态的延续，所以可以和表示一段时间的状语连用于现在完成时态中。如：We haven't seen each other for a long time.
五、练习
（一）用括号中所给词的适当形式填空。
1.She_____(teach)English for three years.
2.People_____(celebrate)the National Day since then.
3.How long_____you_____(be)like this?
4.They____(not write)two letters since last Friday.
5.She_____(work)there for two days.
6._____you ever_____(travel)abroad?
7.I_____never_____(make)a cake by myself.
8.Recently she_____(read)two novels.
9._____she ever_____(ride) a horse?
10.They_____(not finish)the work yet.
（二）根据要求句型转换。
1.They have bought a bike.（否定句）
2.She has been there twice.（划线提问）
3.They have chosen the panda to be symbol.（划线提问）
4.He has drawn three pictures these days.（划线提问）
5.Lucy has lived in Changchun for two years.（划线提问）
6.Daming has driven home.（一般疑问句）
7.Have you brought your homework to school yet?（陈述句）
8.She has sent emails to his friends.（否定句）
9.They haven't been to America.（肯定句）
10.He has had the watch for a year.（划线提问）
（三）句子翻译。
1.他离开上海已经五年了。
2.我父母去上海出差了。
3.你数学作业完成了吗？
4.他们从来不开车上班。
5.我们刚刚参观了这所学校。
6.自从他毕业，他就在这个学校教英语。
7.电影已经开始五分钟了。
8.你看过这本书了吗？
9.在过去的五年里，他学了1000个英语单词。
10.你以前曾获过奖吗？
四、练习参考答案
（一）1.has taught 2.have celebrated 3.have been 4.haven't written 5.has worked 6.Have travelled 7.have made 8.has read 9.Has ridden 10.haven't finished
（二）1.They haven't bought a bike.
2.How many times has she been there?
3.What have they chosen to be symbol?
4.How many pictures has he drawn these days?
5.How long has Lucy lived in Changchun?
6.Has Daming driven home?
7.I have already brought my homework to school.
8.She hasn't sent emails to his friends.
9.They have been to America.
10.How long has he had the watch?
（三）1.He has been away from Shanghai for five years./He has been away from Shanghai since two years ago./It is/ha s been five years since he left Shanghai./Five years has passed since he left Shanghai.
2.My parents have gone to Shanghai on business.
3.Have you finished your maths homework yet?
4.They have never driven to work.
5.We have just visited this school.
6.He has taught English in this school since he left school.
7.The film has been on for five minutes/since five minutes ago.
8.Have you read this book yet?
9.He has learnt 1000 English words in the past five years.
10.Have you won any prizes before?
