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时态构成(时态与语态)

来源:学生作业帮 编辑:作业帮 分类:英语作业 时间:2024/07/05 20:48:17
请写出过去完成时,现在完成时,被动语态的构成并各举例句
解题思路: 如下
解题过程:
现在完成时
现在完成时表示发生在过去的动作一直持续到现在或对现在造成的影响或结果。这种时态的特点是动作发生在过去,但强调其目前的作用。现在完成时可与just, before, now, today, this morning, until(till, up to) now, so far, in the past(last) few years, all day, since 1990, for a long time, recently, lately, always, often, sometimes, ever, never, once, three times, how long等时间状语连用。但不可与yesterday, last week, when等连用。
与一般过去时相比,一般过去时只与过去时间有关,而现在完成时特别强调发生在过去的动作对现在的影响或结果。比较:
He’s lived here since 1960.从1960年以来他一直住在这儿。(“居住”这个动作从1960年一直持续在目前,可能刚刚结束,也可能继续持续下去)
He lived here.过去他住在这儿。(现在情况不详)
He lives here.他住在这儿。(长久动作,不问何时开始,不管何时结束)
注意:
1.It is the first(second...) time +that-从句,that-从句习惯用现在完成时。
It is the second time that I have been here.这是我第二次到这儿来。
2.主句+since从句(从句谓语动词是过去时)中的主句通常用现在完成时。
I haven’t heard from him since he left for Shanghai.自从他去了上海我就一直没收到他的来信。
3.非延续性动词的完成时不可与时间段状语连用。
他去世已经三年了。
(误)He has died for three years.
(正)He has been dead for three years.
(正)Three years has passed since he died.
(正)He died three years ago.
4.现在完成时不可与表示确切时间的过去时间状语连用,也不可与when连用,但可与how long连用。
5.have gone to意为“去了某地(现在已经不在说话的地方)”,have been to意为“去过某地(现在已经不在该地)”。
He has gone to Beijing.他去了北京(现在不在这儿)。  
He has been to Beijing three times.他去过北京三次(现在不在北京)。

过去完成时表示在过去时间里已经完成的动作或状态,即“过去的过去”。这种时态强调过去某一动作的完成,通常和另一稍后发生的过去动作(或某一过去时间)相比。因此,确定两个过去动作的先后或确定某一动作在过去时间前发生是使用过去完成时的关键。
I had written the article when they came.他们来时我已经写完了文章。(“写”在“来”之前已经完成,“来”是过去时,则“写”是“过去的过去”)
By twelve o’clock we had had lunch.十二点前我们就吃完了午饭。
注意:
1. It was+时间段+since-从句中的since-从句习惯用过去完成时。 
It was three years since he had died.他去世已经三年了。 
2.现在完成时的直接引语在变为是过去时的动词的间接引语时,现在完成时要变为过去完成时。
She has made much progress since she came here(She said)→She said she had made much progress since she came here.
被动语态
一、语态概述
英语的语态是通过动词形式的变化表现出来的。英语中有两种语态:主动语态和被动语态。
主动语态表示主语是动作的执行者。
例如:Many people speak Chinese.
谓语:speak的动作是由主语many people来执行的。
被动语态表示主语是动作的承受者,即行为动作的对象。例如:Chinese is spoken by many people.主语English是动词speak的承受者。
二、被动语态的构成
被动语态由"助动词be+及物动词的过去分词"构成。人称、数和时态的变
化是通过be的变化表现出来的。现以speak为例说明被动语态在各种时态中的构成。
一般现在时:am/is/are+spoken
一般过去时:was/were+spoken
一般将来时:will/shall be+spoken
现在进行时:am/is/are being+spoken
过去进行时:have/has been+spoken
现在完成时:have/has been+spoken
过去完成时:had been + spoken
三、被动语态的用法
(1)不知道或没有必要说明动作的执行者是谁。
例如:Some new computers were stolen last night. 一些新电脑在昨
晚被盗了。(不知道电脑是谁偷的)
This bridge was founded in 1981.这座桥竣工于1981年。
(2)强调动作的承受者,而不强调动作的执行者。
例如:The glass was broken by Mike.玻璃杯是迈克打破的。
This book was written by him.这本书是他写的。
Your homework must be finished on time.你们的家庭作业必须及时
完成。
四、主动语态变被动语态的方法
(1)把主动语态的宾语变为被动语态的主语。
(2)把谓语变成被动结构(be+过去分词) (根据被动语态句子里的主语的
人称和数,以及原来主动语态句子中动词的时态来决定be的形式)。
(3)把主动语态中的主语放在介词by之后作宾语,将主格改为宾格。例如:
All the people laughed at him.
He was laughed at by all people.
They make the bikes in the factory.
The bikes are made by them in the factory.
He cut down a tree.
A tree was cut down by him.
五、含有情态动词的被动语态
含有情态动词的主动句变成被动句时,由"情态动词+be+过去分词"构成,原来带to的情态动词变成被动语态后"to"仍要保留。
We can repair this watch in two days.
This watch can be repaired in two days.
They should do it at once.
It should be done at once.
最终答案:略