构成：have/has + done（动词的过去分词） 用法：1. 表示过去发生的动作或状态持续到现在，可能持续下去，常用的时间词有：for + 时间段, since + 时间点, all day, up to now, so far, recently, etc.
I have studied here since 2000.
He has lived in Shanghai for ten years.
2. 表示过去发生的动作或状态对现在造成了影响. 常用的时间词有：already, just, yet, by now, etc.
My friend has already been to Beijing.
Tom has just seen this film. 现在完成时肯定句: have/has + done
现在完成时否定句: haven't/hasn't + done
现在完成时一般疑问句: Have/Has ...?
现在完成时划线提问: question word + have/has ...?
already/just用于肯定句，变否定句或一般疑问句already/just改为yet并将其放在句子的末尾. *already/just用于肯定句，变否定句或一般疑问句already/just改为yet并将其放在句子的末尾. I have already seen this film.
I haven't seen this film yet.
Have you seen this film yet? Yes, I have./No, I haven't.
What have you already seen? 动词的过去分词变化
规则变化与动词的过去式变化规则相同
1.直接加ed
finish - finished - finished
2. e 结尾加d
live - lived -lived
3. 元音+y 直接加ed , 辅音+y 变y为i加ed
play - played - played
try - tried - tried
4. 双写最后一个字母加ed
stop - stopped - stopped
动词的过去分词不规则变化要记忆（有规律可循）
be - was/were - been
go - went - gone
make - made - made
say - said - said
spend - spent - spent
put - put - put
cost - cost - cost
come - came - come
run - ran - run
辨析：
have/has been to ...
have/has gone to ...
have/has been in ... for ... e.g. I have been to Beijing twice.
Tom has gone to Shanghai. He is not at home.
Alice has been in New York for two years. 注意：现在完成时中短暂性动词（ borrow, die, buy, get married）不能与表示延续的时间状语连用，如果连用的话要做相应的转换，在否定句中此类动词可以与表示延续的时间状语连用 He has got married for twelve years. ××
He has been married for twelve years. √√
I have borrowed this book for a week. ××
I have kept this book for a week. √√
The old man has died for three years. ××
The old man has been dead for three years. √√
现在完成时的被动语态 active voice : have/has done
passive voice : have/has been done
e.g.
We have already cleaned the classroom.
The classroom has already been cleaned by us. 一般过去时与现在完成时区别 一般过去时表示过去某个时刻发生的动作，与现在没有关联，和表示过去的时间词连用；现在完成时也表示过去发生的动作，但与现在有关联（动作可能会持续下去或对现在造成影响）
e.g.
He lived here last week.
He has lived here since last week. EET宝山校是沪上最大的青少儿语数英学习教研基地之一，是一所专业、规范的民办教育培训机构。学校以“文化立校”为办学理念，以“质量求信誉”、以“信誉求生存和发展”、以“服务至上”为宗旨，因此，学校办学多年以来在社会上已赢得众多好口碑，深受广大学生和家长们的一致好评！
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