下面小编给大家带来since是什么时态的关键词（共含5篇），希望能帮助到大家!同时，但愿您也能像本文投稿人“AKK”一样，积极向本站投稿分享好文章。
since的用法
1.since作为介词，后接某一确定的时间点，主句谓语动词是持续性动词，常与现在完成时态、现在完成进行时态或过去完成时态连用。
例如：He left the village in 1982 and I haven’t seen him since then.
1982年他离开这个村子，从那以后我再没见过他。
2.since作为副词，表示从过去以来、以后或到现在的情形或状态，常与现在完成时态连用。
例如：He left home two weeks ago and we haven’t heard from him since.
他两周前离开了家，到现在我们一直没有他的`消息。
3.接时间点(谓语动词用现在完成时，而且须是延续性动词。)
例如：I have stayed in that country since 1995.
自从1995年以来我一直呆在那个国家。
4.接一段时间+ago(谓语动词用现在完成时，而且须是延续性动词。)
例如：They have lived in that house since two years ago.
他们两年前就住在那所房子里了。
5.接时间状语从句(主句的谓语动词用现在完成时，而且须是延续性动词;从句的谓语动词用一般过去时，而且须是终止性动词。)
例如：(1)I have loved her since I met her last time.
自从我上次见到她以来，我就一直爱着她。
(2)Lily has stayed at home since she left school.
莉莉自从离开学校就一直呆在家里。
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
I haven't made a sweet today.
我今天没做甜点。
He let us off homework today.
他今天免了我们的家庭作业。
I'm feeling a lot better today.
我今天感觉好多了。
This work has grown in volume recently.
这项工作的量最近增加了。
The reforms have recently become law.
这些改革最近已成为法律。
I've had too many late nights recently.
我最近熬夜太多。
The family has grown in size recently.
这家人最近添丁进口了。
I've had a lot of late nights recently.
最近我常常睡得很晚。
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.
显然，第二句不对，它应改为 Harry got married six years ago. 或 Harry has been married for six years.
★ 随感时态
★ 中考关键词
★ 初中英语时态总结
★ 初中时态说课稿
★ 宾语从句时态
★ 英语时态总结
