人教版中考专题：现在完成时.doc

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2019年中考语法专题：现在完成时
一、语法和句型
【知识梳理】
Present perfect tense (现在完成时)
项目
内容
备注
概念
◇表示一个过去发生的动作对现在产生的结果和影响。
  Eddie has eaten my food.
 (Eddie ate the food and now Hobo has nothing to eat.)
◇表示一个从过去某个时间开始，延续到现在，并有可能继续延续下去的动作或状态。
Eddie has lived with Mille since he was born.
Eddie has lived with Mille for four years.
构成
助动词has/have +动词的过去分词
动词过去分词规则变化跟对应的过去式一样，在后面加ed.特殊变化详见书本。（P122-123）
肯定形式
They have finished their homework.
He has finished his homework.
缩略形式：
they have=they’ve;
he has=he’s
否定形式
They haven’t finished their homework.
He hasn’t finished his homework.
疑问形式
Have they finished their homework?
Yes, they have. / No, they haven’t.
关键词
 
already(用于肯定句), yet(用于否定句和疑问句), since+一点时间, for+一段时间,
never, ever, three times(其它表示频率的词, once, twice等)
before, recently, in the past/last few years, so far, this month, today, now
◇表示过去某一个动作的结果，现在情况依然存在。这时一般不用时间状语。
I have lost my pen.
◇包括现在时间在内的时间状语如today, this month, this week等有时也用现在完成时。
          
2.already与yet用法区别
already 用于肯定句，一般放在助动词与过去分词之间。
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yet用于否定句和疑问句，一般至于句末。
【典例分析】：
I have already worked out this math problem? (改为否定句)    
I                               worked out the math problem                 .  
解析：already与yet的转换.
Key ： have not; yet
since的用法
①since 后面加点时间，如since nearly three years ago或since2008.
②since引导时间状语从句时，后面的时间状语从句动词用一般过去时.
(2) for的用法：for后加一段时间。
since/for 可以通过ago进行同义句转换。
【典例分析】：
1.They have worked in the factory since ten months ago.= They have worked in the factory for ten years
2.We have learned English for nearly three years. =We have learned English since three years ago.
3.I have had a cold _______ last Saturday, I have had a cold ______ 5 days. I have had a cold ______ 5 days ago.
所以：______ 5 days=  ______ 5 days ago
Key ：since，for, since, for, since
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典例分析】：
例1.(   ) I haven’t seen you _____ last Friday.
A. for B. since C. from D. on
解析：后面的last Friday 是具体时间点，所以应