一、在现在完成时态中：现在完成式中瞬间性动词如何变为延续性动词。
1、现在完成时定义：现在完成时既可表示过去发生的动作对现在所造成的结果或影响(此时通常连用的时间状语有already, yet, just, ever, before)，也可表示动作从过去某时间开始，一直持续到现在，并且还有可能持续下去(此时通常连用的时间状语有this month / week / year, these days, recently / lately, in the past few + 时间段, since +时间点, for + 时间段)。如：
I have just finished my work. 我把工作做完。
Have you ever been to Beijing? 你曾经去过北京吗？
I have lived for ten years. 我在这儿住了十年了。
We have studied here since 2003. 我们自2003年来就在这儿读书了。
2. 现在完成时的结构
现在完成时由"have / has + 过去分词"构成。
在现在完成时中,一个瞬间性动词(一次性动作如buy，borrow,die,leave,begin,join等)不能与表示一段时间的状语(for, since, how long等)连用,此时须将该瞬间动词改为延续性动词或状态动词. 这是现在完成时学习的难点和重点。如表所示：
For example:
His father has died.
His father has been dead for three years.
他父亲已经去世三年了。
She has joined the Party/League.
She has been in the Party/ League for two months.=She has been a Party/ League member for two months.
他已经入党/团两个月了。
The film has started/begun.
The film has been on/ lasted since 5 minutes ago.
电影已经开始5分钟了。
He has gone to Kunming..
He has been in Kunming for 3 days.
他已经去昆明三天了。
【习题】When Jack arrived he learned Mary __________ for almost an hour．(leave)
答案：had been away
二、瞬间动词和持续性动词其它用法详解。
（1）瞬间动词表示短暂、不能持续一段时间的动作，如come, go, leave,start, begin, become, receive, die；而持续性动词表示能持续一段时间的动词，如work,stay, live, learn等。
列举一些常用的瞬间动词和持续性动词：
leave离开（瞬间动词）
be away离开（持续性动词）
fall ill生病（瞬间动词）
be ill生病（持续性动词）
borrow借（瞬间动词）
keep借（持续性动词）
catch (a) cold患感冒（瞬间动词）
have a cold患感冒（持续性动词）
buy买（瞬间动词）
have买（持续性动词）
join the army参军（瞬间动词）
be in the army参军（持续性动词）
（2）瞬间动词不能与"for+一段时间"连用，表示动作的持续性，应该改成持续性动词。比如：
√I have bought a calculator.
我已经买了一个计算器。
×I have bought the calculator.
√I have had the calculator for a week.
我买这个计算器已有一个星期了。
下面是一些瞬间动词、持续性动词与现在完成时和一般过去时的连用例子：
James has had the watch for a month.
詹姆士买这个手表一个月了。
James bought the watch a month ago.
詹姆士一个月前买的手表。
My brother has been in the army for some time.
我兄弟参军有一段时间了。
My brother joined the army some time ago.
我兄弟是一段时间以前参的军。
He has been away for two days.
他离开两天了。
He left two days ago.
他离开两天了。
The old man has been dead for ten years.
老人死了十年了。
The old man died ten years ago.
老人十年前去世了。
She has been here for a while.
她到这儿有些时间了。
She came here a while ago.
她刚到这儿。
Nick has been a soldier for a year.
尼克当兵一年了。
Nick became a soldier a year ago.
尼克当兵一年了。
I have known him for five years.
我认识他五年了。
I met him five years ago.
我五年前认为了他。
He has been up for half an hour.
他起床半小时了。
He got up half an hour ago.
他半小时前起了床。
但是瞬间动词的否定结构可以与"for+一段时间"连用，说明某动动作不发生的状态可以持续一段时间。例如：
I haven't met my teacher of English for a year.
我有一年没见到我的英语老师了。
He hasn't returned to his hometown for about ten years.
他约有十年没有回家乡了。
We haven't heard from him for a long time.
我们好长时间没收到他的信了。
（3）瞬间动词的现在完成时（否定式）+since…和持续性动词的现在完成时+since…
注意：since引导的时间状语从句中谓语动词通常用一般过去时。
We have stayed in this school since we came to the city.
我们来到这座城市以来一直住在这个学校。
She has worked in this restaurant since July.
自七月以来他在这个饭店工作。
I have made great progress since he came to teach us English.
自从他来教我们英语，我进步很大。
We haven't written to each other since we left school.
我们毕业以来互相没有通过信。
They haven't met each other since he left.
自从他走了以后他们没见过面。
I haven't seen a film since school began.
开学以来我没有看过电影。
（4）It is + 时间段 + since…自从…
It is two days since he left for America.
他去美国两天了。
It is six weeks since they came here.
他们来这儿六个星期了。
It is about a week since I posted the letter.
这封信我寄出去大约一星期了。
It is a year since they joined the army.
他们参军一年了。
（5）瞬间动词和持续性动词,用于till/until
持续性动词用在含有till/until的句子结构，表示该动作一直持续到某时间终止，而瞬间动词的否定结构用在till/until句子中，表示某动作不发生的状态到某时间终止，可以译为"直到…才…"。比如：
I'll stay till he comes.
我将待到他来。
I won't leave until he comes.
我要他来才离开。
They went on working till supper time.
他们继续工作到晚餐时间。
They didn't stop working till supper time.
他们一直工作到晚餐时间才停止工作。
They lived in the city until the year 2000.
他们在这个城市一直居住到2000年。
They didn't move to another city until the year 2000.
直到2000年他们才搬到另一个城市。
We'll wait until day breaks.
我们将等到天亮。
We won't set out until day breaks.
我们直到天亮才出发。
They slept till noon.
他们一直睡到中午。
They didn't get up until noon.
他们直到中午才起床。
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