现在完成时的构成：助动词have（has）+ 过去分词，
1.表示过去发生或完成的某一动作对现在造成的影响或结果。例如：
I have just cleaned my clothes. 我刚洗过衣服。
（“洗衣服”是发生在过去的动作，对现在造成的结果是“衣服干净了”）
现在完成时常用的时间状语有： already （”已经” 用于肯定句的中间和末尾处）
never （“从不” 用于中间处）
ever （”曾经” 用于疑问句和肯定句的中间处）
just （“刚刚” 用于中间处）
yet （“已经” 用于疑问句的末尾处 / “还” 用于否定句的末尾处）
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。
现在完成时与一般过去时的用法比较
现在完成时表示过去的动作一直延续到现在甚至会继续下去或表示过去的动作对现在造成的影响；一般过去时表示动作发生的时间在过去。试比较：
The plane has arrived . 飞机已经来了。（说明现在的情况：飞机在这儿）
The plane arrived a quarter ago. 飞机是一刻中以前来的。（强调动作发生的时间在过去）
I have taught here for fifteen years. 我在这儿已经教了十五年。（表示十五年前的动作一直延续到现在，还可能会继续。）
I taught here for a year. 我过去在这儿教过一年。（表示“我“现在已经不在这儿任教了）
练习：
I.翻译下列句子：
1. 你曾经吃过鱼和薯条吗？
2. 我刚刚丢了我的化学书。
3. 我以前从来没去过那个农场。
4. 他已经吃过午饭了。
5. 你已经看过这部电影了吗？
6. 我哥哥还没回来。
7. 我上星期看过这部电影。
8. 在1992年他住在这里。
II. 用过去时或现在完成时填空：
1. “_________ you __________ （have） lunch ?” “Yes.”
“When ________ you __________ （have） it?” “I ____________ （have） it at 12:00.”
2. “_________ you __________ （write） a letter to your aunt yet?”
“Yes, I ___________. I ________________ （write） one last week.”
3. “_________ he ___________ （finish） his homework?” “Not yet.”
4. “_________ they ever __________ （be） abroad?” “Yes, just once.”
5. Your father _________ just ___________ （finish） his work.
6. Your father _________ （finish） his work just now.
7. Last term I __________ （learn） many English words.
8. They ____________ （not read） the interesting books yet.
9. He _____________ never ____________ （go） to the science museum.
10. ____________ you ever ____________ （drink） coke?
11. “____________ you _____________ （buy） a dictionary? “ “Yes, I __________ .”
“Where __________ you _____________ （buy） it?” “ I ___________ （buy） it in a bookstore.”
“When ___________ you _____________ （buy） it?” “ Yesterday.”
Since 和 for 的用法
表示过去已经开始持续到现在的动作或状态常用的时间状语有：for, since, how long, so far, these days等。
Since+过去点的时间，for+一段时间（数词+量词），此划线部分用how long提问。
一、since短语或从句表示过去的动作延续至今，since之后的时间为一点。 如：
Mr. Smith has worked here since 1984. 1984年以来，史密斯先生一直在这工作。
He’s learned about 5,000 English words since he went to college. 他上大学以来大约学了五千个英语单词。
二、for短语表示动作延续多长时间，for的宾语为时间段。 如：
We have known each other for twenty years. 我们认识有二十年了。
I haven’t seen her for a long time. 我好久没有见到她了。
练习：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 ago 9） _______ we were children
10） _____ lunch time 11） ______ she left here
1. He has lived in Nanjing ________ the year before last.
2. I’ve known him __________ we were children.
3. Our teacher has studied Japanese _________ three years.
4. She has been away from the city ___________ about ten years.
5. It’s about ten years __________ she left the city.
2.短暂性转换延续性
①arrive at/in sw. get to/reach sw. come/go/move to sw.
→ be in sw./at school/at home/on the farm/be here/be there
1） He got to Beijing five minutes ago.
He ________ _________ _________ Beijing for _________ _________.
2） I moved to the USA last year.
I ________ ________ __________ the USA since __________ __________.
3） I went home yesterday.
I _______ ________ _________ home for _________ __________.
4） They came here last week.
They _________ _________ here since _________ __________.
②come/go back, return → be back come/go out → be out
1） He came out two years ago.
He _________ __________ _________ for __________ __________.
2） We return to Fuzhou yesterday.
We ________ ________ _________ to Fuzhou since __________.
③become → be
1） I became a teacher in 2000.
I ________ __________ a teacher for _________ _________.
2） The river became dirty last year.
The river _________ _________ dirty for _________ __________.
④close → be closed open → be open
1） The shop closed two hours ago.
The shop ________ _________ _________ for _________ _________.
2） The door opened at six in the morning.
The door ________ ________ ________ for six hours.
⑤get up → be up die → be dead
leave sw. → be away from sw.
fall asleep/get tot sleep → be asleep
finish/end → be over marry → be married
1） I got up two hours ago.
I ________ ________ ________ since ________ ________.
2） He left Fuzhou just now.
He _______ ________ ________ _________ Fuzhou for five minutes.
3） My grandpa died in 2002.
My grandpa _______ _______ ________for _______ ________.
4） The meeting finished at six.
The meeting ________ ______ ______ for six hours.
5） I got to sleep two hours ago.
I ________ _________ _________ since _________ __________.
6） They married in 1990.
They ________ _________ __________since _________.
⑥start/begin to do sth. → do sth. begin → be on
1） I began to teach at this school in 1995.
I ____ ____ at this school since ____.
2） The film began two minutes ago.
The film ____ ____ ____ for ____ ____.
⑦borrow → keep lose → not have buy → have put on → wear
catch/get a cold → have a cold get to know → know
1） They borrowed it last week.
They _________ _________ it since __________ __________.
2） I bought a pen two hours ago.
I _________ _________ a pen for ________ __________.
3） I got to know him last year.
I _________ __________ him since __________ __________.
4） I put on my glasses three years ago.