since的具体用法

希望老师就近几年英语考试中牵扯到有关since具体用法以及关于since的语法句型等等讲一下......

解题思路： 如下
解题过程：
since 的用法及相关结构是高中英语的重点内容，在历届及各省市的高考试卷中均有涉及。
例如，在2008年全国I卷里有这样一道题；
[2008.全国卷I]----Have you known Dr. Jackson for a long time ?
-----Yes ,since she ______the Chinese Society .
A.
has joined
B. joins
C. had joined
D.joined
正确答案是D；从四个备选选项上看，这道题是在考察时态的问题，而事实上，正确答案的选择是由句中的since来决定的。
since 从句中时态若为一般过去时，则主句的时态是现在完成时或现在完成进行时。在问句中出现了现在完成时的时态，所以since从句中要使用过去时的时态；且since 从句的谓语动词一般是非延续性动词（终止性动词）。
I have written home four times since I came here .
She has been working in this factory since she left school.
It be +时间段+since 从句；自从....以来到现在多久了。
当主句be动词是is/has been 时，since从句中谓语动词用一般过去时；
当主句be动词是was时，since从句谓语动词用过去完成时。
since 从句的谓语动词为非延续动词（终止性动词）；时间计算一律从since从句的动作完成或状态结束时算起。
It is /has been two years since his father died .他的父亲去世两年了。
=His father has been dead for two years .
=His father died two years ago .
It is /has been four years since he went abroad to further his studies.他去国外深造已经四年了。
=He went abroad to further his studies two years ago .
(2005.北京，春) I t is almost five years ______ we saw each other last time .
A. before
B. since
C. after
D. when

since 之后若出现延续性动词，其含义为“不做某事已多长时间了”。
It is three years since I smoked a cigarette .我不吸烟已经三年了。
(2005.安徽，29)That was really a splendid evening .It’s years ______ I enjoyed myself so much.
A. when
B. that
C. before
D. since
[D]
该句译为；我已经好几年没有玩得这么愉快了。
另外，since还可以表示“既然，由于”之意，引导原因状语从句，例如：
Since you can't answer the question, perhaps we'd better ask someone else.
既然你无法回答这个问题，我们最好再问问别人。

最终答案：略