It is +时间段+since+从句
It has been +时间段+since+从句 此句型的要点：
Eg: It is(has been) ten years since I joined the army 译为:我参军已经十年了.
Eg: It is(has been) ten years since I was a teacher =It is(has been) ten years since I left the army 译为:我复员十年了.
It is ten years since I smoked =It is ten years since I stopped smoking 译为:我戒烟十年了.
1、－What was the party like？－Wonderful. It’s years____ I enjoyed myself so much
A: after B:before C:when D:since
2、I live in Beijing now, that’s to say, it’s ten years since I ____Beijing.
A:lived in B:left for C:left D:was in
3、I’m a teacher now, that’s to say, it is ten years since I___ a teacher.
A: have been B: was C:became D:turned Key.
【答案：1、D 2、B 3、C】