现在完成时
一. 用法：
（1）动作发生在过去，强调对现在的影响。
与一般过去时的区别：
强调过去—一般过去式
强调对现在的影响---现在完成时。
试比较：
I have lost my new book. 我把新书丢了。（现在还未找到）
I lost my new book yesterday. 我昨天把新书丢了。（昨天丢的，现在找到与否没说明）
My mother went to Shanghai.
Where is your mother? ---She has gone to Shanghai.
. I didn’t have breakfast.
I haven’t have breakfast yet.
（2）动作发生在过去某个不确定的时间，但对现在有某种影响和结果。常被just、already、yet 等副词修饰。如：
--Have you had lunch yet? --Yes, I have. I've just had it.
你（已经）吃午饭了吗？我刚刚吃过。（现在我不饿了）
（3）现在完成时表示未完成。动作从过去延续到现在，还可能以后继续。通常和带有for和since等表示一段时间的状语。
He has been in the army for ten years.
I have studied English since 1980.
（4）表示说话前发生过一次或多次的动作，现在成为一种经验，一般译为汉语“过”，表示次数：一次once; 二次: twice, 三次：three times…, ever, never等时间状语。
如：I have been to Beijing twice.我去过北京二次。
I have been to Shanghai twice.
She has watched this film three times.
I have never seen more beautiful girl than she.
练习
1. 我已经在深圳住了十年。
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2. 我的叔叔自从1960年以来都在寻找他的女儿。
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3. 我踢足球已经有两年了。
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4. 我自从1996年就认识玛丽
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5. He has lived in Nanjing ________ the year before last.
6. I’ve known him __________ we were children.
7. Our teacher has studied Japanese _________ three years.
8. She has been away from the city ___________ about ten years.
9. It’s about ten years __________ she left the city.
二. 构成：
(1) 肯定句：have / has done
(2) 否定句：...have/has not done
(3) 一般疑问句：Have/ Has ... done ....?
Yes, ... have/has. No, ...have/has not.
(4) 常用的时间状语有：
already“已经”肯定句的中间和末尾处
never“从不”中间处
ever“曾经”疑问句和肯定句的中间处
just“刚刚”中间处
yet “已经” 、“还”疑问句、否定句的末尾处)或不加任何的时间状语，但不能和表示过去的时间状语连用.
A.already和yet区别:
I have already finished my homework.
already用在_______，位于_______。“已经”
Have you finished your homework yet?
yet用在_______和________中，位于_______。“仍然，还，已经”
B.for 与since区别: for +时间段since+ 时间点
I have lived in Changchun__________ two years.
I have been here__________7 o'clock.
用since和for填空
1. ______ two years
2._______ two years ago
3. _______ last month
4.______ 1999
5._______ yesterday
6. _______ 4 o’clock
7. ______ 4 hours 8._______ an hour 9. _______ we were children 10. _____ lunch time 11.______ she left here 12, _______ she was very young
13. _______ she was a child 14, _____ more than twenty years
三.have been in,have been to与have gone to的用法区别
（一）.have(has) been in 表示“在某地呆多长时间”，常与表示一段时间的状语连用，如：since, for, how long 等。例如：
Mr. Brown has been in Shanghai for three days. 布朗先生来上海已经有三天了。
此外还有这些搭配：have been here (there) /at home (school) /on the farm
have been here (there) / abroad
（二）.have(has)been to表示“曾经去过某地”，现在已经不在那里了。可与just, ever, never等连用，例如：
I have just been to the post office. 我刚才去邮局了。
Mary has never been to the Great Wall. 玛丽从未去过长城。
Have you ever been to Hangzhou? 你曾经去过杭州吗？
