现在完成时
现在完成时定义：表示动作发生在过去，并且对现在产生某种影响或造成某种结果。
（一）基本结构
现在完成时的句子结构一般为：
*肯定句：主语 have/has 过去分词 其他成分
（主语为第三人称单数时，用has, 不是三单时用have）
如：
We have already had lunch.
He has been away for a week.
* 一般疑问句：
Have / Has 主语 动词过去分词。。。？
肯定回答： Yes，I have. / She has.
否定回答： No, I haven’t. / She hasn’t
例如
Have you had lunch yet ? Yes, I have.
Has he been away for a week ? No, he hasn’t.
*否定句
主语 haven’t / hasn’t 动词过去分词。。。
例如
I haven’t had lunch.
He hasn’t been away for a week.
（三）动词的过去分词
1、规则变化
其变化规则与动词的一般过去时基本相同，主要是在词尾加-ed或-d。具体的有：
1）直接加-ed。如：worked、played。
2）以不发音的e结尾的动词后加-d。如：lived、danced。
3）以辅音字母加y结尾的动词后改y为i，再加-ed。如：studied、cried。
4）以重读闭音节结尾的动词后，双写最后一个辅音字母再加-ed。如：stopped、patted。
2、不规则变化
如果结合动词的过去式，动词的过去分词的不规则变化中，又有一些相对的规则现象。如：
1）AAA型。如：put put put；read read read。其中，read的过去式和过去分词虽然拼写时一样的，但其发音与原形不同，ea不再读作[i?]，而是[e]。
2）AAB型。如：beat beat beaten
3）ABB型。如：keep kept kept；sit sat sat
4）ABC型。如：lie lay lain；drink drank drunk
5）ABA型。如：run ran run；e came e
时间状语
1、副词already用于肯定句、yet用于一般疑问句和否定句
Just 刚刚 before 以前, 放在句末 。
如：
She has already arrived in Shanghai.
She hasn't arrived in Scotland yet.
They have just left for Shanghai.
He hasn’t watched TV before.
2、for和since。for 一段时间，since 1999/ two years ago / 过去时。
如：
He has learned Italian for five months.
He has learned Italian since five months ago.
He has learned Italian since 1999.
He has learned Italian since he came to Italy.
3、so far和up to now /till now 。表示“迄今为止”。如：
So far, no one has heard any news about her.
She has read fifty books up to now.
4、recently、lately等表示“最近；最新”的副词和形容词。如：
I've met her on several oasions recently.
He hasn't had enough sleep lately.
5、in the past/last 一段时间，表示“在过去的...时间里”。如：
In the past few years, new buildings have sprung up all over Beijing.
He had aged rapidly in the last few months.
6、次数, never, ever 如：
I've tried many times, but there's no way.
He has been there at least twice.
They have already e back from the museum.
She has already finished her homework.
非延续性动词：动作发生即结束
延续性动词：动作可以持续进行。
句子中如有for 时间段和since 时间点，必须用延续性动词，若是非延续性动词必须改为延续性动词或变成系表结构。
非延续性动词 --------------- 延续性动词
Leave ---- -- be away
borrow ----- keep
buy ---- have
die ---- be dead
Join------ be in / be a member of ...
Start / begin --- be on
例句：
I have left for Beijing .
I have been away for Beijing for two days.
例句
The movie has started.
The movie has been on since three minutes ago.
例句
He has died.
He has been dead for two years.
错误：He has died for ten years.
正确：He has been dead for ten years.
错误：She has married him since five years ago.
正确：She has been married to him since five years ago.
3、表示从过去某一时间到说话时这段时间中反复发生的动作。
此时，常和谓语动词一起使用的主要是表频度的副词often、always、seldom、never等，以及表次数的单词或短语（如once、twice、three times）。
如：
You have never listened to me like this before.
She has ever been to France.
They have visited the Summer Palace many times.
（五）have been to/have gone to/have been in
1、have been to
表示“去过已回”。句子主语就在现场。如：
They have been to Rome many times.
She has been to Shanghai more than once.
2、have gone to
表示“去了未回”。句子主语不在现场。如：
Jerry has gone to Hangzhou.
Mary has gone to Finland.
3、have been in 通常与for 时间段连用
表示“一直待在某地”。如：
We have been in Beijing for five weeks.
They have been in China since 2012.
（七）句型转换
因为“have/has done”中的have/has是助动词，
所以在进行句型转换中要注意不需要再另外借助助动词do/did/does，而是直接借用have/has。如：
肯定句：He has lived here for the last few years.
否定句：He hasn't lived here for the last few years.
一般疑问句：Has he lived here for the last few years?
特殊疑问句：How long has he lived here? （划线部分为for the last few years
总结：
现在完成时
1.定义：表示动作发生在过去，并且对现在产生某种影响或造成某种结果。
2.基本结构
现在完成时的句子结构一般为：
*肯定句：主语 have/has 过去分词 其他成分
（主语为第三人称单数时，用has, 不是三单时用have）
* 一般疑问句：
Have / Has 主语 动词过去分词。。。？
肯定回答： Yes，I have. / She has.
否定回答： No, I haven’t. / She hasn’t
*否定句：主语 haven’t / hasn’t 动词过去分词。。。
3. 时间状语：already, yet, just, before, so far, till now, up to now, for 时间段，since 时间点，
4. 短语：have/ has been to , have/ has gone to, have/has been in
5. for 时间段，since 时间点，有这两个短语时，要用延续性动词。
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