一．现在完成时知识点:
1.用法：
(1)表示过去发生或已经完成的动作对现在造成的影响或产生的结果。
e.g. I have already finished my homework.
She has already read this book.
Mary and Tom have finished their lunch.
(2)也表示过去发生的动作从过去一致延续到现在，也可能是将来，此用法常与延续性动词连用。
e.g. I have studied English for three years.
She has lived here for eight years.
Tom has worked there since 1998.
They have been here since they graduated.
2.常与现在完成时搭配的时间状语（标志词）：
(1) yet还（用于否定句和疑问句）；
(2) already早已，已经（用于肯定句）；
(3) for + 一段时间（a year，three months，etc.）；
(4) since + 表示过去的时间点；
(5) so far到目前为止；
(6) ever曾经；
(7) in the past few years（months，days，etc.）；
(8) up to now直到现在；
(9) before以前；
(10) by + 现在的时间点，意为“截至……时”；
(11) by the end of + 现在的时间点，意为“截至……时”；
(12) over + 时间段，意为“在……期间”等。
e.g. I haven’t had lunch yet.
Maryhas already read this book.
3.形式: have/has（助动词） + done（动词的过去分词）
4.主谓一致：
(1) have done：主语为I或者复数名词，代词，词组或是句子；注意此结构中的have为助动词，无实际意义；
(2) has done: 主语为单数名词，代词，词组或是句子；注意此结构中的has为助动词，是have的三单形式。
e.g. Tom and his father have gone to Shanghai.
The film has been on for half an hour.
5.动词过去分词的转变规则：
(1)规则变化：和动词过去式的转换规则一致；
(2)不规则变化：需特殊记忆（有些相同，有些不同）。
6.现在完成时中肯定句，否定句及一般疑问句的相互转化以及一般疑问句的肯定和否定回答（与含有助动词的句子的转换规则一致）。
e.g. (1)肯定句：I have read the book.
否定句：I haven’t read the book.
一般疑问句：Have you read the book?
肯定回答：Yes, Ihave.
否定回答：No. I haven’t.
(2)肯定句：She has finished lunch
否定句：She hasn’t finished lunch.
一般疑问句：Has she finished lunch?
肯定回答：Yes, she has.
否定回答：No. she hasn’t.
7.现在完成时常与“since + 句子”连用，since从句用一般过去时，主句用现在完成时。
e.g. I have studied Japanese since I graduated from university.
She has worked here since she came Shanghai.
8. have/has been (to…) 与have/has gone (to…) 的用法辨析:
(1) has/have been (to…) 意为“到过某地”，说话时此人已经不再那个地方，可能已经回来，强调经历；
(2) has/have gone(to…) 意为“已经去了某地”，说话时此人已经不再这里，很可能已经到达那个地方或是在路上。
e.g. He has been to Beijing.
He has gone to Beijing.
Where has Tom been?
Where has Tom gone?
9.瞬间动词与延续性动词的用法辨析:
(1)瞬间性动词指不能够持续的动词，如go，come，arrive，die等，不能与一段时间连用。
(2)延续性动词表示可以持续的动词，如stay，live，wait等。
e.g. She has gone to Shanghai.
I have lived in the place for three years.
10.现在完成时与一般过去时的用法辨析:
(1)一般过去时只表示过去的动作，现在完成时强调过去的动作对现在造成的影响或产生的结果。
e.g. I read the book last year.
I have read the book.
(2)现在完成时的动作开始于过去而且现在还在继续，而一般过去时的动作早已结束。
e.g. He has worked in this company for three years.
He has worked in this company for three years.
(3)现在完成时表示动作发生在过去一个不确定的时间，常与already，yet，never，before等连用；一般过去时表示在过去某个确定的时间发生，常与过去具体的时间连用。
e.g. I have already read the book.
I lived in the countryside three years ago.
(4)用how long来询问“for +一段时间”或是“since +过去的时间点”，而且这三个词必须与延续性动词连用。
e.g.①How long have you had that bike over there?
I’ve had it for three years.
②How long has his son owned the train and railway set?
He’s owned it since his fourth birthday.
11. 动词过去式（过去分词）的转化:
(1)规则动词的转化规则：
①一般情况下直接加-ed；
e.g. look----looked
play----played
start----started
②以-e结尾的动词加-d；
e.g. live----lived
hope----hoped
use----used
face----faced
③以重读闭音节（通常是一个元音字母加上一个辅音字母）结尾的，且末尾只有一个辅音字母的，双写这个辅音字母，再加-ed；
e.g. stop----stopped
plan----planned
permit----permitted
beg----begged
④以辅音字母加-y结尾的动词，变-y为-i再加-ed。
e.g. study----studied
carry----carried
worry----worried
(2)不规则动词的变化规则，需特殊记忆：
①原形，过去式和过去分词形式相同：
e.g. hit----hit----hit
set----set----set
put----put----put
cut----cut----cut
cast----cast----cast
cost----cost----cost
shut----shut----shut
hurt----hurt----hurt
burst----burst----burst
spread----spread----spread
②过去式和过去分词同形：
e.g. feed----fed----fed
bleed----bled----bled
bend----bent----bent
buy----bought----bought
breed----bred----bred
fight----fought----fought
bring----brought----brought
catch----caught----caught
sell----sold----sold
leave----left----left
meet----met----met
send----sent----sent
find----found----found
sleep----slept----slept
teach---taught----taught
think----thought----thought
③原形，过去式和过去分词均不相同：
e.g. lie----lay----lain
see----saw----seen
rise----rose----risen
give----gave----given
begin----began----begun
blow----blew----blown
know----knew----known
grow----grew----grown
break----broke-----broken
drink----drank----drunk
speak----spoke----spoken
swim----swam----swum
二．习题专练及参考答案：
（一）习题专练：
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