7、----It’s five years since I worked here.
---- ?
A、Have you worked here happily B、How long will you work here
C、Where do you work now D、Do you want to work here longer
为什么选C呢？~具体解释一下~

It’s five years since I worked here. 这句意思是：我不在这里工作已经有五年了

注意work是个延续性动词

要是表达“我在这里工作五年了”应该是
It's five years since I got a job here. 而get是非延续性动词
since后面是 延续性动词 和 短暂性动词，意义是不一样的
你这样记吧，要是since后面是 延续性动词，则表达的意思是否定意思，否则就是肯定意思。
再例如It's five years since I smoked.我我戒烟有五年了
I.表示“做某事已有多久了”，since从句中要使用中止性动词。



It is almost 20 years since the war ended.战争结束后差不多二十年了。= Almost 20 years have passed since the war ended.



It’s a long time since I met you last.我们已经分别很久了。



II.表示“没做某事已有多久了”，since 从句要使用延续性动词或者是状态动词。



That was really a splendid evening. It’s years since I enjoyed myself so much. 好几年我都没那么高兴过了。



It is three years since I have seen you.我已经有3年没有看见你了。



It’s a long time since he studied English 他好久没学英语了。
It is five years since he smoked.=It is five years since he stopped smoking.他戒烟已经三年了。



[since+延续性动词的过去式：时间从延续动词结束后计算，即表示的是否定含义。]