it is 600 years since the first clock with a face and an hour hand was made.中since能换成before吗?

This morning I went to the English corner which is in the park near my home.It is three years sinc AIthough it is almost 600 years old,but it is still very brautiful改错 It is five years since he smoked It is been years的句子结构 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 People say that it is 100 years old.同义句------- --------that it is 100 years old. It is anyhow cleaner than it was 100 years ago Angel is twelve years old.It is her birthday today 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 It is years since we meet last time.（纠错） It is three years since she was in the It is five years ___ Mr Wang ___ the car this is it.five years.you are not alone forever. It is ten years since he ____(join) the army It is more than tow thowsand years old it is 3 years since Tom has been abroad It is forty years since he home 改为间单句 it is long years sine I _____ (live) here