现在完成时讲解
一．基本结构：助动词have/has+过去分词(done)
二．句型：
否定句：主语+have/has+not+过去分词+其他. 一般疑问句：Have/Has+主语+过去分词+其他.
简略答语: Yes, 主语+ have/has.(肯定) No, 主语+ haven't/hasn't.(否定)
三．用法
（1）现在完成时表示过去发生或已经完成的动作对现在造成的影响或结果
I have spent all of my money (so far).(含义是:现在我没有钱花了.)
Guo zijun has (just/already) come. (含义：郭子君现在在这儿)
My father has gone to work.(含义是:我爸爸现在不在这儿) （2）现在完成时可以用来表示发生在过去某一时刻的,持续到现在的动作（用行为动词表示）或状态（be动词表示）常与for（+时间段）,since（+时间点或过去时的句子）连用.
①for+时段
②since+过去一个时间点（译为：自从……以来）
③since+时段+ago
④since+从句（过去时）
●⑤It is+时段+since+从句（过去时）
Mary has been ill for three days.
I have lived here since 1998.
四．has gone (to),has been (to), has been (in) 的区别
Have/Has gone(to) :去了(现在不在说话现场)
Where is your father？He has gone to Shanghai.
Have/Has been (to) :去过（已不在去过的地方）
My father has been to Shanghai.
Have/has been in：呆了多久（还在所呆的地方）
My father has been in Shanghai for two months. /since two months ago.
五．现在完成时的标志
1. 现在完成时的含义之一是过去完成的动作对现在仍有影响,用以下四大标志词可以表达这种含义: * 以already, just和yet为标志
He has already got her help. 他已得到她的帮助。
He has just seen the film. 他刚刚看过这场电影。
He hasn't come back yet. 他还没有回来。
* 以ever和never为标志
This is the best film I have ever seen. 这是我曾经看过的最好的一部电影。
He has never been to Beijing. 他从没有到过北京。
* 以动作发生的次数为标志
He says he has been to the USA three times. 他说他已经去过美国三次了。
* 以so far（到目前为止）为标+before
He has got to Beijing so far. 到目前为止他已到了北京。
She has passed the examso far. 到目前为止她已经通过了考试。
2.过去已经开始的动作一直延续到现在, 甚至有可能继续延续下去,我们可以从动作“延续”的特性和“时间”点段的区分入手,进一步学习现在完成时。
* ①for+时段②since+过去一个时间点（过去从句）为标志
注意：1)现在完成时不能单独与过去的时间状语连用, 如yesterday,last week, three years ago 等; 2)不能与when连用 2.现在完成时往往同表示不确定的过去时间状语连用
六．过去分词
1 、规则动词：规则动词的过去分词的构成规则与规则动词的过去式的构成规则相同。
四点变化规则：
(1)、一般动词，在词尾直接加“ ed ”。
work---worked---worked ,visit---visited---visited
(2)、以“ e ”结尾的动词，只在词尾加“ d ”。
live---lived---lived ,
(3)、以“辅音字母+ y ”结尾的动词，将"y" 变为"i" ，再加“ ed ”。
study---studied---studied ,cry---cried---cried
(4)、重读闭音节结尾，末尾只有一个辅音字母，先双写该辅音字母，再加“ ed ”。
stop---stopped---stopped , drop---dropped--dropped
2 、不规则动词见不规侧动词变化表：
特殊词：
★1.have代替buy
My brother has had(不能用has bought) this bike for almost four years. ★2、用keep或have代替borrow
I have kept(不能用have borrowed) the book for quite a few days.
★3、用be替代become
How long has your sister been a teacher?
★4、用have a cold代替catch a cold
Tom has had a cold since the day before yesterday.
★5、用wear代替put on
b)用“be＋形容词”代终止性动词
1、be＋married代marry
2、be＋ill代fall (get) ill
3、be＋dead代die
4、be＋asleep代fall (get) asleep
5、be＋awake代wake/wake up
6、be＋gone代lose,die,sell,leave
7、be＋open代open 8、be closed代close/shut
9、be＋missing(gone,lost)代lose
c)用“be＋副词”代终止性动词
1“be＋on”代start,begin
2“be＋up”代get up
3“be＋back(to)”代return to,come back to,go back to
4“be here (there)”代come(arrive,reach,get) here或go (arrive,reach,get) there等等
d)用“be＋介词短语”代终止性动词
1.“be in/at +地点”代替go to /come to
2.用be in the army 代替join the army
3.“be in/at +地点”代替move to
常用瞬间动词变延续性动词表：
1. have arrived at/in sw. got to/reached sw. come/gone/moved to sw.
→have been in sw./at…相应的介词
2. have come/gone back/returned → have been back
3. have come/gone out →have been out
4. have become →have been
5. have closed / opened→ have been close/open
6. have got up → have been up；
7. have died → have been dead；
8. have left sw. → have been away from sw.
9. have fallen asleep/got to sleep → have been asleep；
10. have finished/ended/completed → hav e been over；
11. havemarried → have been married；
12. have started/begun to do sth. → have done sth. ；
13. have begun → have been on
14. have borrowed/bought →have kept/had
15. have lost → haven’t had
16. have put on →have worn
17. have caught /get a cold → have had a cold；
18. have got to know → have known
19. have/has gone to → have been in
20. have joined/have taken part in the league/the Party/the army。