英语现在完成时与过去完成时区分

现在完成时与过去完成时的区别
学生往往在初学现在完成时和过去完成时感到比较容易掌握，但在实际运用中却难以准确把握。究其原因 主要是对两者的 区别认识不清。下面将两者的 区别概括总结如下： （一）从概念上区别：1）现在完成时表示过去发生的某一动作对现在造成的结果或影响，也可指过去开始 延续到现在的动作或状态。2）过去完成时表示在过去某一动作或时间 以前已发生或完成的 动作，也可指从过去某时开始 到过去某时为止的 动作或状态，即“过去的 过去”。 （二）从结构上区别 现在完成时：主语 + have / has + 过去分词 （肯定式） 主语 + have / has + not + 过去分词 （否定式） Have / Has + 主语 + 过去分词 （疑问式） 过去完成时：主语 + had + 过去分词 （肯定式） 主语 +had + not + 过去分词 （否定式） Had + 主语 + 过去分词 （疑问式） （三）从时间 状语区别 现在完成时: 常用的 时间 状语包括 “now, today, tonight, this week, this year, already, yet, just, recently…etc”。 过去完成时: 常用的 时间 状语包括 “by, at, before等构成的 短语”。 注意：当表示一段时间 ，现在完成时和过去完成时都可以用for 或since引导的 状语。 例如：Have you had your lunch yet? 你吃午饭了吗？ Yes, I have . I’ve just had it. 是的 ，我刚吃完。 I have had a clock now. 我现在有一个闹钟了。 Have you already posted the photos? 你把照片寄走了吗？ The meeting had begun when we got there. 我们到那儿时，会议已经开始 了。 We had learned about 5000English words by the end of last term. 到上学期末我们已经学了5000个英语单词。 They had done the work at five o’clock. 在五点钟的 时候他们已经完成了那项工作。 I’ve known Li Lei for three years. 我认识李蕾已经三年了。 I have worked here since ten years ago. 自从十年前我就在这工作。 We had not heard from him since we left here. 自从我们离开以来一直没有收到他的 来信。 They had then been without sleep for twenty-four hours. 这时他们已经有24个小时没有合眼了。 （四）使用时注意事项 使用现在完成时应该注意： 1.“ have/ has got ”形式上是一种完成时，但和have/ has 为同一意义，即 “有”。 例如：Have you got a pen-friend? 你有笔友吗？ Yes, I have. 是的 ，我有。 Has he got a lot of work to do? 他有许多工作要做吗？ No, he hasn’t. 不，他没有。 2. have/ has gone to 与 have/has been to 的 区别 have/ has gone to 强调“去而未归”； have/ has been to 强调“去而归还”。 have/ has been to常和once, twice, never, ever连用； have/ has gone to则不可。例如： — Have Jack ever been to Beijing? 杰克去过北京 吗？ — Yes, he’s been there several times. 是的 ，他去过好几次了。 — Where have Mary and Tom gone? 玛丽和汤姆去哪里了？ — They’ve gone to London. 他们去伦敦了。 3.非延续性动词不能用于“现在完成时 + 表示一段时间 的 状语”的 句型中。 这类动词有：come, go, start, leave, die, buy, finish, join, borrow, stop等。但它们能够 用表示持续状态的 相应的 延续性动词替换句中的 终止性动词。例如： arrive, come → be here, be in begin, start → be on buy → have die → be dead fall asleep(ill) → be asleep (ill) finish, end → be over get to know → know get up → be up go out → be out join → be in , be a + 名词 leave, move → be away, be out of 使用过去完成时应该注意： 如果两个动作紧接着发生，则常常不用过去完成时。例如： When she came into the room, she found them sitting together singing. 她 进屋时看见他们坐在一起唱歌。 After we said good-bye to our friends, we left the village. 在和朋友告别之后我们就离开村子。

现在完成时 强调对现在的影响，一般和 过去的段时间连用.

例如:Mike has been away for a long time.

过去完成时　　往往发生在过去某个动作前，所谓"过去的过去？，经常和一般过去时态的　状语从句（尤其是时间状语从句）连用

例：He had worked in the firm before he came here.
现在完成时枣表示到目前为止已经完成，并对现在留下某种后果和影响的动作。
结构：助动词have/has + 动词的过去分词 用法: 1.表示过去发生的某一动作对现在造成的影响或结果,常与一些时间状语,如:already, yet, ever, never, just, before, once,twice等连用,也可以和包括现在在内的时间状语,如these days,today,this year,so far等连用.

2.表示过去发生的动作或存在的状态,一直持续到现在,也许还将继续下去,可以和表示从过去某一时刻延续到现在的一段时间的状语连用,即for +时间段,since+时间点/从句, in the last ten years等,谓语只可用延续性动词.
4.现在完成时和一般过去时的区别
现在完成时所表明的是过去发生的动作对现在的影响,强调的是现在的情况,不可以和表示过去的时间状语yesterday,in 1991,three days ago last time,last night等连用.
5.现在完成时中的 for 与 since
for + 时间段 与延续性动词的现在完成时连用
since + 时间点/从句
I have kept the library book for a week.= I have kept the library book since a week ago.
6. It is /has been +一段时间 + since 从句.自从某事发生已有一段时间了.
eg. It is /has been two years since my brother joined the army.
过去完成时枣表示过去某一时间或动作之前已完成的动作
结构： 助动词had + 动词的过去分词
用法： 1.表示在过去某一时间或动作之前已经发生或完成了的动作,动作发生的时间为“过去的过去“.表示过去某一时间可用by,before 等构成的短语,也可用when,before等引导的从句或通过上下文表示.
eg. By the end of last term,we had learned a thousand English words.
He had finished his homework before his father came back last night.
2.表示过去某个时间之前发生的动作或状态, 一直延续到这一过去时刻,或还将继续下去.
eg. When I got to know him, he had worked there for twenty years.
(注意) 否定式 had not == hadn't
时态的呼应
1.主句中谓语动词如果是现在时或将来时,从句中的谓语动词可以用任何所需要的时态,
he wants to speak to the headmaster. He said that he won't be free tomorrow.
he came last night.

2.主句中的谓语动词如果是过去时态,从句中的谓语动词一般情况下要用过去时态的某种形式.
He said that he was working hard on his Chinese.

he had a very good journey home.

he hadn't bought the present yet.

he would stop in Moscow on the way.

3.如果从句所述内容是客观真理,则谓语动词总是用一般现在时,而不受主句中谓语动词时态的影响.

eg. Miss Gao told us that light travels much faster than sound.

4.时间或条件状语从句中,若主句是一般将来时或祈使句,从句要用一般现在时代替将来时.
eg.Stop talking when the headteacher ______(walk)into the classroom.
Jim won't watch TV until he ___ (finish) his homework every time.

have done
had done