第1个回答 2013-09-01
现在完成时
定义：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,也可表示过去已经开始,一直延续到现在的动作或状态。
构成:主语 + have/has + 过去分词 + 其他。当主语是第三人称单数时用has,其余人称用have。过去分词:规则动词的过去分词构成与动词过去式相同;在动词后面加ed构成过去分词。
否定式:主语 + haven't/hasn't + 过去分词 + 其他。
疑问式: 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)
常见判断词：so far, recently,by now,ever since(从那时起)，for+时间，since,ever,already,yet,in the past few years,by the end of +表示现在的时间（this term----）
例如：she has been a doctor for twenty years
My mother has worked in the hospital since in 1985.
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
already, just和yet 表示到现在为止动作或状态已经、刚刚或还没有发生。
* 以ever和never为标志
ever和never 表示到现在为止动作或状态曾经或从来没有发生过。
* 以动作发生的次数为标志
若某一动作到现在为止已经发生了若干次,则要使用现在完成时。
* 以so far为标志
so far往往表示到目前为止动作或状态已经发生。
基本用法
1) 表示过去发生或已完成的某个动作对现在产生的影响或结果，强调的是这个影响或结果，常同already, just, yet等状语连用
例：I have just turned off the light. 我刚刚把灯关上。（结果是灯已经关上了）
She has lost her bike. 她把自行车丢了。（影响是他现在没有自行车骑了）
The rain has stopped now. 雨已经停了。（结果是我们可以出门了）
I have already read the book. 我已读过这本书了。（结果是已知道这本书的内容）
She has had a good education. 她受到过良好的教育。（影响是她文化水平高，有修养）
2) 表示开始于过去、持续到现在的动作或状态，并可能继续下去（也可能不继续下去），常同包括现在在内的时间状语连用，如：today, now, this week, this morning, these days, this afternoon, recently, so far等；也同“for+时间段”或 “since＋时间点”的状语连用
例：We have had much snow this winter. 今年冬天多雪。
She has taught in the school for ten years. 她在这所学校教书已经10年了。
I haven't eaten anything since breakfast. 我从早饭起就一直没有吃东西。
We have been busy this morning. 今天上午我们一直很忙。
I have known her since we were children. 我从小就认识她。
I haven't seen John today. 我今天没有见到约翰。
It has rained a lot these days. 这些天多雨。
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或多次动作的总和，常同频度副词always, often, seldom, never等连用
例：He has done a lot of work in the past two years. 在过去两年中他做了许多工作。
I have learned about two hundred English words this morning. 本月我学了大约200个英语单词。
I have been to the Great Wall twice. 我曾经去过长城两次
It has rained every day this week. 这个星期天天下雨。
She has always walked to school. 她一直步行去学校。
I have never seen such a beautiful bird. 我从没见过这么美丽的鸟。
I have often met the old man on my way to work. 我在上班的路上常常遇见那位老人。
4) 现在完成时与一般过去时的区别
1．现在完成时为过去发生的，强调过去的事情对现在的影响，强调的是影响，而一般过去时与现在没有联系，只是说明某个动作发生的时间是在过去,强调动作。
比：I have washed the car. 我洗过了车。（看上去很漂亮）
I washed the car a moment ago. 我刚才洗过车了。
She has watered the flowers. 她已经浇了花。（不需要再浇了）
She watered the flowers yesterday. 她昨天浇的花。
2.现在完成时表示的动作或状态延续到现在并可能延续下去，而一般过去时则单纯表示过去某段时间内的经历。
比：It has rained for five hours. 雨已经下了5个小时了。
It rained for five hours yesterday. 昨天下了5个小时的雨。
3．过去时常与具体的时间状语连用，而现在完成时通常与模糊的时间状语连用，或无时间状语
4.现在完成时可表示持续到现在的动作或状态，动词一般是延续性的，如live, teach, learn, work, study, know.
过去时常用的非持续性动词有come, go, leave, start, die, finish, become, get married等。
举例：
I saw this film yesterday.
（强调看的动作发生过了。）
I have seen this film.
（强调对现在的影响，电影的内容已经知道了。）
非延续性动词不能与时间段连用：
go/come/begin/start/die/buy/borrow/sell/leave/arrive/
receive/become等词语是瞬间动词表示的动作是一时的，不能延续，不能与for、since等表示一段时间的词连用，也不能用于how long引导的疑问句中。
如不能说：He has borrowed the book for two months.(ⅹ)
但可以说：He has kept the book for 2 months.
或：It has been 2 months since he borrowed the book.
或：Two months has passed since he borrowed the book.
这些瞬间动词常与它对应的可以表示时间段的词语进行互换。
become—be borrow—keep buy—have
begin (start)—be on open—be open die—be dead
leave--be away come--be here/in go out—be out
join--be a member/be in begin to study--study
如果非延续性动词用于现在完成时的否定式，则可同一段时间状语连用，并可同“for＋一段时间”或“since＋一时间点”和“since＋句子”连用。
例：She hasn't left home for a year. 她离开家还不到一年。
I haven't seen Jamie for two months. 我两个月没见杰米了。
用于现在完成时的句型
1）It is the first / second time…. that…结构中的从句部分，用现在完成时。
It is the first time that I have visited the city.
It was the third time that the boy had been late.
2）This is the… that…结构，that 从句要用现在完成时.
This is the best film that I've (ever) seen.
这是我看过的最好的电影。
This is the first time (that) I've heard him sing. 这是我第一次听他唱歌。
典型例题
(1) ---Do you know our town at all?
---No, this is the first time I ___ here.
A. was B. have been C. came D. am coming
答案B. This is the first time 后面所加从句应为现在完成时，故选B。
(2) ---Have you ____ been to our town before?
---No, it's the first time I ___ here.
A. even, come B. even, have come C. ever, come D. ever, have come
答案D. ever意为曾经或无论何时，反意词为never，此两词常用于完成时。 This is the largest fish I have ever seen. It is / was the first time +that-clause 的句型中，从句要用完成时。
注意：非延续性动词的否定形式可以与表示延续时间的状语连用。即动作不发生的状态是可以持续的。
（错）I have received his letter for a month.
（对）I haven't received his letter for almost a month
现在完成时
定义：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,也可表示过去已经开始,一直延续到现在的动作或状态。
构成:主语 + have/has + 过去分词 + 其他。当主语是第三人称单数时用has,其余人称用have。过去分词:规则动词的过去分词构成与动词过去式相同;在动词后面加ed构成过去分词。
否定式:主语 + haven't/hasn't + 过去分词 + 其他。
疑问式: 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)
常见判断词：so far, recently,by now,ever since(从那时起)，for+时间，since,ever,already,yet,in the past few years,by the end of +表示现在的时间（this term----）
例如：she has been a doctor for twenty years
My mother has worked in the hospital since in 1985.
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
already, just和yet 表示到现在为止动作或状态已经、刚刚或还没有发生。
* 以ever和never为标志
ever和never 表示到现在为止动作或状态曾经或从来没有发生过。
* 以动作发生的次数为标志
若某一动作到现在为止已经发生了若干次,则要使用现在完成时。
* 以so far为标志
so far往往表示到目前为止动作或状态已经发生。
基本用法
1) 表示过去发生或已完成的某个动作对现在产生的影响或结果，强调的是这个影响或结果，常同already, just, yet等状语连用
例：I have just turned off the light. 我刚刚把灯关上。（结果是灯已经关上了）
She has lost her bike. 她把自行车丢了。（影响是他现在没有自行车骑了）
The rain has stopped now. 雨已经停了。（结果是我们可以出门了）
I have already read the book. 我已读过这本书了。（结果是已知道这本书的内容）
She has had a good education. 她受到过良好的教育。（影响是她文化水平高，有修养）
2) 表示开始于过去、持续到现在的动作或状态，并可能继续下去（也可能不继续下去），常同包括现在在内的时间状语连用，如：today, now, this week, this morning, these days, this afternoon, recently, so far等；也同“for+时间段”或 “since＋时间点”的状语连用
例：We have had much snow this winter. 今年冬天多雪。
She has taught in the school for ten years. 她在这所学校教书已经10年了。
I haven't eaten anything since breakfast. 我从早饭起就一直没有吃东西。
We have been busy this morning. 今天上午我们一直很忙。
I have known her since we were children. 我从小就认识她。
I haven't seen John today. 我今天没有见到约翰。
It has rained a lot these days. 这些天多雨。
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或多次动作的总和，常同频度副词always, often, seldom, never等连用
例：He has done a lot of work in the past two years. 在过去两年中他做了许多工作。
I have learned about two hundred English words this morning. 本月我学了大约200个英语单词。
I have been to the Great Wall twice. 我曾经去过长城两次
It has rained every day this week. 这个星期天天下雨。
She has always walked to school. 她一直步行去学校。
I have never seen such a beautiful bird. 我从没见过这么美丽的鸟。
I have often met the old man on my way to work. 我在上班的路上常常遇见那位老人。
4) 现在完成时与一般过去时的区别
1．现在完成时为过去发生的，强调过去的事情对现在的影响，强调的是影响，而一般过去时与现在没有联系，只是说明某个动作发生的时间是在过去,强调动作。
比：I have washed the car. 我洗过了车。（看上去很漂亮）
I washed the car a moment ago. 我刚才洗过车了。
She has watered the flowers. 她已经浇了花。（不需要再浇了）
She watered the flowers yesterday. 她昨天浇的花。
2.现在完成时表示的动作或状态延续到现在并可能延续下去，而一般过去时则单纯表示过去某段时间内的经历。
比：It has rained for five hours. 雨已经下了5个小时了。
It rained for five hours yesterday. 昨天下了5个小时的雨。
3．过去时常与具体的时间状语连用，而现在完成时通常与模糊的时间状语连用，或无时间状语
4.现在完成时可表示持续到现在的动作或状态，动词一般是延续性的，如live, teach, learn, work, study, know.
过去时常用的非持续性动词有come, go, leave, start, die, finish, become, get married等。
举例：
I saw this film yesterday.
（强调看的动作发生过了。）
I have seen this film.
（强调对现在的影响，电影的内容已经知道了。）
非延续性动词不能与时间段连用：
go/come/begin/start/die/buy/borrow/sell/leave/arrive/
receive/become等词语是瞬间动词表示的动作是一时的，不能延续，不能与for、since等表示一段时间的词连用，也不能用于how long引导的疑问句中。
如不能说：He has borrowed the book for two months.(ⅹ)
但可以说：He has kept the book for 2 months.
或：It has been 2 months since he borrowed the book.
或：Two months has passed since he borrowed the book.
这些瞬间动词常与它对应的可以表示时间段的词语进行互换。
become—be borrow—keep buy—have
begin (start)—be on open—be open die—be dead
leave--be away come--be here/in go out—be out
join--be a member/be in begin to study--study
如果非延续性动词用于现在完成时的否定式，则可同一段时间状语连用，并可同“for＋一段时间”或“since＋一时间点”和“since＋句子”连用。
例：She hasn't left home for a year. 她离开家还不到一年。
I haven't seen Jamie for two months. 我两个月没见杰米了。
用于现在完成时的句型
1）It is the first / second time…. that…结构中的从句部分，用现在完成时。
It is the first time that I have visited the city.
It was the third time that the boy had been late.
2）This is the… that…结构，that 从句要用现在完成时.
This is the best film that I've (ever) seen.
这是我看过的最好的电影。
This is the first time (that) I've heard him sing. 这是我第一次听他唱歌。
典型例题
(1) ---Do you know our town at all?
---No, this is the first time I ___ here.
A. was B. have been C. came D. am coming
答案B. This is the first time 后面所加从句应为现在完成时，故选B。
(2) ---Have you ____ been to our town before?
---No, it's the first time I ___ here.
A. even, come B. even, have come C. ever, come D. ever, have come
答案D. ever意为曾经或无论何时，反意词为never，此两词常用于完成时。 This is the largest fish I have ever seen. It is / was the first time +that-clause 的句型中，从句要用完成时。
注意：非延续性动词的否定形式可以与表示延续时间的状语连用。即动作不发生的状态是可以持续的。
（错）I have received his letter for a month.
（对）I haven't received his letter for almost a month