现在完成时:其构成: have (has) +done
用法:
1)表示过去发生的动作对现在的影响或结果;
I’ve seen the film Avatar before.
2)表示持续到现在的动作或状态。
They’ve lived there for eleven years.
比较过去时与现在完成时
1)过去时表示过去某时发生的动作或单纯叙述过去的事情,强调动作;现在完成时强调过去的事情对现在的影响,强调的是影响。
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。)
2)过去时常与具体的时间状语yesterday, last week,…ago, in1980, in October, just now等连用,而现在完成时通常与模糊的时间状语for, since, so far, ever, never, just, before, yet, till / until, up to now, in past years, always等连用,或无时间状语。
共同的时间状语:
this morning, tonight, this April, now, once,before, already, recently,lately
3)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。
用于现在完成时的句型
1)It is the first / second time…. that…
It is the first time that I have visited the city.
2)This is the… that…
This is the best film that I''ve (ever) seen.
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。
I haven''t received his letter for almost a month.
比较since和for
since 用来说明动作起始时间,for用来说明动作延续时间长度。
I have lived here for more than twenty years.
I have lived here since I was born..
My aunt has worked in a clinic since 1949.
注意:并非有for 作为时间状语的句子都用现在完成时。
I worked here for more than twenty years. (我现在已不在这里工作。)
I have worked here for many years.(现在我仍在这里工作。)
延续动词与瞬间动词
1) 用于完成时的区别
延续动词表示经验、经历; 瞬间动词表示行为的结果,不能与表示段的时间状语连用。
He has completed the work. (表结果)
I''ve known him since then. (表经历)
2)用于till / until从句的差异
延续动词用于肯定句,表示"做……直到……"; 瞬间动词用于否定句,表示"到……,才……"
He didn''t come back until ten o''clock.
He slept until ten o''clock.
1.把考察放在从句中增加难度;2.和被动语态放在一起考察;3.根据状语确定时态4.用现在完成时的句型
1.现在完成和一般过去弄混;2.现在完成时的句型不熟悉;3. 不能根据状语选定现在完成时。
【典型例题】
1. You don''t need to describe her. I ___ her several times.
A. had met B. have met C. met D. meet
解析:错选C。首先本题后句强调对现在的影响,我知道她的模样,你不用描述;再次,“several times” 表示“(到目前为止)我(已经)见过她 “好几次”了,因此用现在完成时,答案B。
2. ---I''m sorry to keep you waiting.
---Oh, not at all. I ___ here only a few minutes.
A. have been B. had been C. was D. will be
解析:错选C。等待的动作由过去开始,持续到现在,应用现在完成时,答案A。
3. ---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
解析:错选D。This is the first time 后面所加从句应为现在完成时,答案B。
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