It __four years since i joined the army.这里的is,为什么不用was呢?

It __four years since i joined the army.这里的is,为什么不用was呢? This morning I went to the English corner which is in the park near my home.It is three years sinc It start many years since+瞬间性动词的疑问It is two years since you come to see me.It is two years since you come here.since后面+的都是瞬间性动词,但第一句表示的是否定,两年没看了,第二句表示的是肯定来了两年了.请问这个sinc It was 85 years还是 it has been 85 years? it's years since i since 3 years ago.是时间点还是时间段3 years ago.是时间点还是时间段.2.since 1985 是时间点 还是时间段?3.It is +一段时间+ since从句.怎么翻译?自从.已经多少年了》?是这样翻译吗我在网上查的说，sinc In the course of the meeting,it was suggested that our discussion __________ down.阶一In the course of the meeting,it was suggested that our discussion __________ down.was written should write wrote be written It has been more than three years sinc It took them ten years ------- the bridge It three years since I smoked.翻译 It was three years before he came It is five years since he smoked It's over 900 years old. it was about 100 years ago What will it be six years It is been years的句子结构 it's seems like years since it's been It is anyhow cleaner than it was 100 years ago