现在完成时
1.构成
现在完成时是由助动词 have(has)+动词的过去分词done构成。助动词have说明该谓语是属于现在时范围。它和主语的人称、数要保持一致。过去分词done是主要的谓语动词，说明句子的意义。
2.用法
（1）表示动作发生在过去某个不确定的时间，但对现在留下了某种影响和结果。常和just、already、yet 等副词连用。如：
---Have you had dinner yet?你（已经）吃晚饭了吗？
---Yes，I have. I've just had it. 我刚刚吃过。（强调现在我不饿了）
（2）表示从过去某一时刻开始一直持续到现在的动作或状态。这个动作可能刚停止，可能仍然在进行。常和for和since等表示一段时间的状语连用。
如：He has livedin Beijing since 2001.
他自从2001年就住在北京了。（可能还要继续住下去）
（3）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”，常带有ever，never，twice，three times等时间状语。
如： I have been to Shanghai three times.我去过上海三次。
3．结构
1）陈述句结构：主语＋have/has（not）+过去分词＋其它。
have not=haven't has not=hasn't.
2）一般疑问句结构：Have(Has )＋主语＋过去分词＋其它。
3）特殊疑问句：特殊疑问词＋have(has) +主语+ 过去分词＋其它。
例如：She has already seen the film.
She hasn’t seen the film yet.
Has she seen the film yet?
Yes，she has./ No，she hasn't.
4.现在完成时的时间状语
现在完成时属于现在时范围，故不能和过去的时间状语连用。但是，在强调动作产生的后果和影响时，可以和一些表示不确定的时间状语连用。有 already，yet，since，for，ever，never，just，before，up to now等。
如：We have already finished our homework.我们已完成作业了。
They haven't finished their homework yet.他们还没有完成作业。
I have never been to the Great Wall.我从未去过长城。
We have studied English for three years. 我们（开始）学英语已三年了。
5.几点注意事项
（1）have been to与have gone to的区别：have been to表示“去过某地（现在已经回来了）”，可用于各人称；have gone (to)表示“去某地了（说话时某人不在当地）”，常用于第三人称，前者可与once，never，several times 等连用，后者则不能。
如：They have been to Beijing twice.他们去过北京两次。
He has gone to Beijing . 他去北京了。
（2）如单纯表示一段时间，或强调一段时间，虽有since一词，也不必用完成时。
如：It is two years since his father died. =His father has been dead for two years. 他父亲去世已有三年了。
（3）终止性动词现在完成时的否定式，已变成一种可以延续的状态，因此可以和表示一段时间的状语连用。
如：I haven't left here since 1997.自从1997年以来，我一直没有离开过这儿。 练一练：
一、用since和for填空。
1. Jill has been in Ireland Monday.
2. Jill has been in Ireland three days.
3. Mike has been ill a long time. He has been in hospital October.
4. Margaret is in her office. She has been there 7 o'clock.
5. India has been an independent country 1974.
二、用所给动词的适当形式填空。---词形大“变态”。
1. He (live) in Beijing since he was born.
2. My friend, Chang Li, (buy) a new car last week.
3. We (not hear) from them for a long time.
4. I (not read) the book before.
5. Mother (make) me a new coat yesterday.
6. I (see) him go into the hotel just now.
答案见下期
上一期答案：
A、用动词的适当形式填空。
1) It_was__( be ) Ben’s birthday last Friday.
2) __Are___they going to_sweep___ ( sweep ) the floor on Sunday? No，they__aren’t___.
3) We all__had___ ( have ) a good time last night.
4) Jim __is___going to plant( plant) trees tomorrow.
5) She likes__reading___newspapers，but she __read___a book yesterday. ( read ).
6) He __is playing__football now，but they __played__basketball just now.( play ) .
7) I _am__going to watch( watch ) a cartoon next Monday.
B、按要求改写句子。
1) My father came to the shop just now.（改为否定句）
My father___didn’t __ __come__ to the shop just now.
2）I’m going to get up at 6:30 tomorrow.（改一般疑问句）
__Are_ __you__ __going__ to get up at 6:30 tomorrow?
3) Their teacher told them a story yesterday.（对划线部分提问）
_What_ __did_ their teacher___tell__them yesterday?
4）She is going to listen to music after school.（对划线部分提问）
__What__ __is___ she__going___ __to___ ___do__ after school?
5) David and Liu Tao did their homework together a moment ago.（改为一般疑问句）
_Did__ David and Liu Tao_do_ __their_ homework together _just_ _now_.
