初二英语下册 第6单元

八年级下册英语第六单元课件
张一凡▲现在完成时的基本用法
①表示过去发生的某一动作对现在造成的影响。

I have just received a letter from my brother.
我刚刚收到我哥哥的来信。

Have you seen the film?
你看过这部电影吗?
I have been to New York three times so far.
我到现在为止已经去过纽约3次了。

②表示过去已经开始，持续到现在的动作或状态，往往和表示一段时间的状语连用。

I have not seen him since last January.
我自去年一月就没有看见过他。

Li Hong has been abroad for three years.李红已经出国3年了。

Up till now he has won five prizes.
到现在为止他已赢得5块奖牌了。

③现在完成时常与不确定的时间状语连用。

如：already，never，ever，just，yet，before，up to now，so far，for the last few weeks等，表示“到目前为止”所发生的动作。

She has just got a little cold.她只是有点感冒。

Have you read this book?你看过这本书吗?
Has he paid the doctor yet?他给医生交过钱了吗?
I have never met such a strange person.
我以前从没遇见过这么奇怪的人。

It hasn’t rained for six months.已经6个月没有下雨了。

Great changes have taken place in this city in the last five years.
在最近的5年当中，这个城市发生了巨大的变化。

④现在完成时还可以和包括现在在内（到说话时仍未结束的）的，表示一段时间的状语连用，如；now，today，this morning／afternoon／evening／week／month／year／these days，since，for a long time等。

I have finished my homework now.
我已经完成了我的家庭作业。

They have visited the Great Wall today.
他们今天游览了长城。

We have had enough rain this autumn.
今年秋天我们这里的雨水很足。

▲现在完成进行时态
现在完成进行时态，表示从过去某一时刻开始一直延续到现在的动作，这动作可能仍然在进行。

主语＋have been＋doing 表示“从过去开始一直持续到现在，有可能还要持续下去的动作”。

如：
I have been collecting coins since I was ten years old.我从十岁起就一直在搜集钱币。

She has been dancing for two hours.到现在她跳舞已经有两个小时了。

上面句子中collect, dance这两个动作从过去某个时间开始，一直持续到现在，还可能继续下去上句答语中since＋（过去的）时间点，表示“自从……（过去某个具体时间）以来”，而for＋时间段，表示动作持续的时间。

如：
What books have you been reading these days?
这些天你都看些什么书?
I’ve been sitting here all afternoon.
我在这儿坐了一下午了。

They have been collecting stamps for ten years.
他们收集邮票已经10年了。

Has she been watching TV?她一直在看电视吗?
▲since的四种用法
1) since +过去一个时间点(如具体的年、月、日期、钟点、1980, last month, half past six)。

I have been here since 1989.
2) since +一段时间+ ago
I have been here since five months ago.
3) since +从句
Great changes have taken place since you left.
Considerable time has elapsed since we have been here.
4) It is +一段时间+ since从句
It is two years since I became a postgraduate student
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.
Some new oilfields have been opened up since 1976.
I have known Xiao Li since she was a little girl.
My brother has been in the Youth League for two years.
I have not heard from my uncle for a long time.
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。

小窍门：
当现在完成时+一段时间，这一结构中，我们用下面的公式转化，很容易就能排除非延续动词在完成时中的误使。

1)(对) Tom has studied Russian for three years.
= Tom began to study Russian three years ago, and is still studying it now.
2)(错) Harry has got married for six years.
= Harry began to get married six years ago, and is still getting married now.
第二句不对，它应改为Harry got married six years ago.或Harry has been married for six years.。