现在完成时的几个问题现在完成时的语法是规定在句末加上时间短语时：for+时间段,since+时间点那时间段和时间点的区别是什么呢?最好是文字说明再加例句说明

现在完成时的几个问题现在完成时的语法是规定在句末加上时间短语时：for+时间段,since+时间点那时间段和时间点的区别是什么呢?最好是文字说明再加例句说明
现在完成时的几个问题
现在完成时的语法是规定在句末加上时间短语时：for+时间段,since+时间点
那时间段和时间点的区别是什么呢?
最好是文字说明再加例句说明

现在完成时的几个问题现在完成时的语法是规定在句末加上时间短语时：for+时间段,since+时间点那时间段和时间点的区别是什么呢?最好是文字说明再加例句说明
since
表示从什么时候开始
例子 since 2004
是指 2004到现在
for
是指一段时间
例子 for 2004 to 2006
指的是04年到06年
SINCE后面加时间点
例如 SINCE 1990 意思就是从1990开始
1990就是一个时间点；
而FOR后面是加时间段
例如 FOR 5 YEARS
意思就是5年的时间
since+过去某一时间或句子,for+一段时间
She has taught in the school for ten years. 她在这所学校教书已经10年了.
I haven't eaten anything since breakfast. 我从早饭起就一直没有吃东西.

for+时间段谓语动词要是延续性动词
since+时间点谓语动词是非延续性动词

since是自从什么时候开始到现在为止！
后接一个时间点。
I have kept this book since 4 weeks ago
for是一个时间段！
后接一段时间
I have kept this book for 4 weeks
注（超重要）：瞬间动词（buy,die,join,lose……）不能直接与for since 连用。要改变...

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since是自从什么时候开始到现在为止！
后接一个时间点。
I have kept this book since 4 weeks ago
for是一个时间段！
后接一段时间
I have kept this book for 4 weeks
注（超重要）：瞬间动词（buy,die,join,lose……）不能直接与for since 连用。要改变动词
come-be
go out-be out
finish-be over
open-be open
die-be dead
………………
1.have代替buy
My brother has had(不能用has bought) this bike for almost four years.
2、用keep或have代替borrow
I have kept(不能用have borrowed) the book for quite a few days.
3、用be替代become
How long has your sister been a teacher?
4、用have a cold代替catch a cold
Tom has had a cold since the day before yesterday.
5、用wear代替put on
b)用“be＋形容词”代终止性动词
1、be＋married代marry 2、be＋ill代fall (get) ill
3、be＋dead代die 4、be＋asleep代fall (get) asleep
5、be＋awake代wake/wake up 6、be＋gone代lose,die,sell,leave
7、be＋open代open 8、be closed代close/shut
9、be＋missing(gone,lost)代lose
c)用“be＋副词”代终止性动词
1“be＋on”代start,begin
2“be＋up”代get up
3“be＋back(to)”代return to,come back to,go back to
4“be here (there)”代come(arrive,reach,get) here或go (arrive,reach,get) there等等
d)用“be＋介词短语”代终止性动词
1.“be in/at +地点”代替go to /come to
2.用be in the army 代替join the army
3.“be in/at +地点”代替move to
常用瞬间动词变延续性动词表：
1. have arrived at/in sw. got to/reached sw. come/gone/moved to sw.
→have been in sw./at…相应的介词
2. have come/gone back/returned → have been back
3. have come/gone out →have been out
4. have become → have been
5. have closed / opened→ have been close/open
6. have got up → have been up；
7. have died → have been dead；
8. have left sw. → have been away from sw.
9. have fallen asleep/got to sleep → have been asleep；
10. have finished/ended/completed → have been over；
11. havemarried → have been married；
12. have started/begun to do sth. → have done sth. ；
13. have begun → have been on
14. have borrowed/bought →have kept/had
15. have lost → haven’t had
16. have put on →have worn
17. have caught /get a cold → have had a cold；
18. have got to know → have known
19. have/has gone to → have been in
20. have joined/have taken part in the league/the Party/the army
→have been a member of/ have been in/have been the Party’s member/the league member/the soldier…

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